This is a fan-made, non-commercial tool developed for personal purposes and private use. It stands entirely on the work of the Umamusume community. Special thanks to all the people who reverse-engineered the mechanics, translated the game and made various tools and simulators. The sources this tool followed are as follows:

Disclaimer: This project is an experiment for personal/private usage, I don't claim the information to be correct. If anything, there's lots of things that may be incorrect as there are lots of uncertain variables in uma's mechanics. Please keep this in mind.

The Japanese is translated with AI and may not be perfect. Sorry for any mistakes, and I am happy to fix them if you spot any.

The game
Cygames — Umamusume: Pretty Derby

The game itself of course. All assets belong to Cygames.

Data, translations & art
GameTora

Skill icons, the stat emblems, and the character portraits.

Kamigame

Stat emblem artwork.

UmaTL — hachimi-tl-en

The community English translations for skill, uma, and course names.

noccu — umamusu-translate

The master.mdb text-category map, and the original community translation effort (now continued as Hachimi).

Engine, mechanics & tools
alpha123 — uma-skill-tools

Reference, validation, course data and inspiration

alpha123 — uma-tools (umalator)

Used for reference and validation.

mee1080 — umasim

Used for reference and validation, and whose import/export format this tool is based on.

rockisch — umamusu-utils

The MIT asset-extraction approach my data pipeline is modeled on.

U-tools (攻略.tools)

Each uma's theme colours, and used for cross-validation.

KuromiAK & the mechanics doc

The race-mechanics documentation my engine was mainly built on.

Built with
Next.js · React · Tailwind CSS · Base UI · TanStack Table · dnd-kit · cmdk · Zod · lucide

The stack this site runs on.

v0.53.1
  • Grandstand: captured replays now use each uma's exact in-game evaluation score, keeping the rank consistent on entrant cards, in the editor, in batch reports, and in View build.
v0.53.0
  • Build Wizard: steps two through four are clearer on mobile and desktop, with improved support-card controls, optional course selection, simpler skill filters, keyboard-accessible skill chips, and a build summary that stays visible while you work.
  • Uma builds: import a full detail screenshot made with Receipt Factor Maker. The importer reads the character version, stats, aptitudes, rank, and skills, then lets you inspect the source image and correct any skill before saving.
  • Saved teams: create and edit teams of up to 18 saved umas. The Grandstand can load a team into the field, show each uma's rank, and prefer replacing a chosen team when space is limited.
  • Grandstand: Stamina Keep now follows its captured timing and recovery behavior more closely. It can end and restart after a recovery skill, remain active through the finish, and uses final Wisdom when deciding whether to conserve.
  • Race sets: each uma's summary now shows how often it entered Stamina Keep instead of average finish time.
v0.52.0
  • Build Wizard: green aptitude skills like Left Turns or Medium Distance Straights now offer their double circle version too. A card hint for the single circle lets you upgrade to the double circle for free in game, so both are shown and you can pick either.
  • Build Wizard: the training scenario now defaults to the newest available scenario, while remaining changeable for older scenarios.
  • Support cards: added the artwork for the latest cards that were showing a blank placeholder, including the four newest SSRs.
  • Uma builds: the editor now uses the same running-style and motivation badges seen elsewhere, improves the form layout, and can preview the finished uma before saving.
  • Uma builds: the preview can now be downloaded or copied as a PNG, including the complete skill list for long builds.
v0.51.0
  • Build Wizard: you can now pick the training scenario you are building for. The skill step then adds that scenario's exclusive gold skills and offers its evolutions, showing each base gold alongside the pink it turns into in that scenario.
  • Build Wizard: reworked (strengthened) umas that have more than one evolution for the same skill now offer both. Sweep Tosho, for example, can take either Sylphic Magia or Nox Lumina for Unrivaled Wits. The newest is picked by default.
  • Skill icons: many newer skills that were showing a blank placeholder now display their proper icon, including the トレセン軒 scenario skills and the roughly 160 skills the game draws with a generic effect icon.
v0.50.0
  • Builds: a new Uma builds tab turns a build into a real uma. Pick a character to load her aptitudes and unique, apply the skills from a saved support deck, edit skills, and save her so she is ready to race in the Grandstand.
  • Builds: an experimental Build Wizard walks you through it. Pick the uma and set up her inheritance (two parents and four grandparents, each offering their inherited unique, with the evolved version available from a direct parent), build a support deck and choose each card's event options, pick the track and running style you are building for, then choose skills. The skill step gathers the golds and white hints your cards and chosen events give, the skills your inheritance offers, and the uma's own evolutions (picked by default, or settle for the plain gold or white version), and can trim everything down to what actually works on your track.
  • Data dictionary: a skill's details now list its related skills, the other tiers of the same skill (the single and double circle whites and the gold) and any evolutions.
  • Fix: 22 characters who start at 1 or 2 stars (Gold Ship, Vodka, Daiwa Scarlet, Grass Wonder, El Condor Pasa, Air Groove, and more) had their 3 star unique treated as an evolution by mistake. Their ult was loading at level 1 with no unique bonus, which under-rated them and weakened that skill in races. It is now correctly their unique, at full level.
v0.49.1
  • Japanese: references to the JP server have been removed from Japanese copy, where it is simply the normal server. The English wording still identifies the app's supported region for global players.
  • Home: the Builds card now describes its support-deck planning, available-skill browsing, and reusable build and skill-list features.
v0.49.0
  • Builds: support-card decks and the card picker now match the game's layout more closely, with rarity frames, support-type emblems, a compact 3-by-2 deck, type counts, and newest-first card sorting within SSR, SR, and R.
  • Builds: deck setup and the finished build are now clearer separate steps. Saved builds show when they are being edited, updates ask before overwriting, reset and bulk skill controls are easier to find, and skill names use consistent sizes with full names on hover.
  • Builds: reusable skill lists can now be saved from the current selection, imported, exported, and added to another build. Their skills can also be toggled individually, and a Recommended area is ready for event-specific lists.
v0.48.4
  • Japanese: the Grandstand's Known caveats note is now fully translated. A sentence added to it later had still been showing in English.
  • Consistent design across the app: the shared game styling from the Grandstand is now used everywhere. The uma detail popup's running-style chip matches the strat chips used elsewhere, and the unique (ult) skill's iridescent gradient is identical wherever it appears, including the rarity pills in the data dictionary's skills table.
v0.48.3
  • Japanese: the recently added features that were still showing English are now translated — the bulk replay bar, the Saved umas opponent library and its import dialog, the race set launcher, the Grandstand debug overlay setting, and the Received buff/debuff toggle.
  • Japanese: the Builds section reads 編成 again everywhere (two spots had slipped back to ビルド), the race view's mechanics toggle now reads 挙動 to match its own tooltip, and the race report's phase markers use the standard leg names (中盤 / 終盤 / ラストスパート). English users no longer see Japanese phase labels there.
  • Replays: mechanic spans in the results table (oikurabe, kakari, and the rest) no longer read 101 to 102 percent. A mechanic still active as the uma crosses the line is now shown ending at 100 percent.
v0.48.2
  • Grandstand on mobile: you can now scroll the page past the race view. A vertical swipe over the race canvas scrolls the page instead of being swallowed by it, so it no longer traps your finger. A horizontal drag still pans along the track, tapping still selects an uma, and scrolling past no longer knocks the camera out of Fit or Follow.
v0.48.1
  • Mobile: popups now fit the screen and stay closable. On phones, a tall popup like the Grandstand race statistics report or the skill detail popup could open partly above the top of the screen, putting the close button out of reach, and scrolling a long popup carried the close button away with it, so there was no way out. Popups now size to the visible screen, scroll inside a fixed frame with the close button always in reach, and can be dismissed by tapping outside. This applies to every popup in the app.
  • Mobile: in the uma detail popup, the stat values and aptitude labels no longer overflow their cells. On narrow screens the rank glyph and number shrink so a four-digit over-cap stat fits, and the aptitude labels and grade glyphs shrink so a three-character label (マイル, 短距離…) stays on one line. The layout is unchanged on larger screens.
v0.48.0
  • New game data: adds Phalaenopsis (with her skills and portrait) and two more support cards from the current JP patch, Zenno Rob Roy (SR) and Machikane Tannhaeuser (SSR) with their event golds, plus the patch's remaining new and evolved skills. Skills, support cards, and text are refreshed to the patch.
  • Race engine: the Gambler skills (勝負師 and its evolution 鉄火のギャンブラー) now take effect. They use a random-activation condition the engine did not recognize, so their Speed/Power/Guts boost was being skipped. It now applies, treated as the roll passing (the same way the sim handles other pre-race lotteries), and picks the right tier by popularity.
  • One brand-new effect code, on Nakayama Festa's evolved All-in!!, is not simulated yet and currently does nothing; that skill's other effects and every other new skill work normally.
v0.47.0
  • New game data: updated to the latest JP patch. Adds two new umas, Shinko Windy and Fenomeno, with their skills and portraits, and four new support cards (Haru Urara, Biko Pegasus, and two Samson Big cards) with their event golds and hint pools. Skills, support cards, and text are refreshed to the patch.
  • All of the new skills use effects the race engine already simulates, so they work normally in both the single-uma simulator and the Grandstand. A few brand-new skill icons and the new cards' art may show a placeholder until the art source publishes them.
v0.46.0
  • Grandstand: you can now load many captured replays at once instead of one at a time. Pick several replay files (or a whole folder of them) in the Load replay dialog and they open together as a set, with a bar above the track to step through them: a row of race buttons for a few, a dropdown when there are many, plus Previous and Next and a Clear. If a folder is all one track, you are asked which course only once and it applies to the whole set.
  • Grandstand: a new Stats button opens a report across all the loaded replays, in the same style as the Race set report. It shows each uma's win, podium, and average finish across the set, out-of-stamina and rush counts, and a per-race list you can open and click to jump straight to that replay. Umas are identified by character and trainer and by their skill build, so two similar builds of the same uma stay separate, and a control lets you hide umas that appear fewer than a chosen number of times.
  • Grandstand: you can share a whole set of replays with a single link, up to 50 at a time. The set is compressed to fit in one link, and opening it loads the entire set for the other person, ready to browse and view its stats.
  • Grandstand: shared replays no longer include the race's random seed or internal race id, so a shared replay can no longer be traced back to the exact real race it was captured from. Trainer names and builds are kept. This applies to both single replays and shared sets.
v0.45.1
  • Loaded replays: the results table now shows when an uma ran out of stamina during the race. This comes from the captured HP data but was always reading No before, so an uma who ran dry before the line now shows where it happened (as a percentage of the race), the same way the simulator reports it.
  • Loaded replays: the results table now shows every time an uma entered stamina conserve (持久力温存), not just the first. It can happen more than once in a race, so the Conserve column now shows the overall span, a count when it recurred, and the total time spent conserving, with each occurrence listed in the tooltip.
v0.45.0
  • New game data: updated to the latest JP patch. Adds two new umas, Epiphaneia and Rulership, plus new outfits for Seiun Sky, Mejiro Bright, and Fusaichi Pandora, and seven new SSR support cards (Kiseki, Almond Eye, Fusaichi Pandora, Red Desire, Efforia, Mr. C.B., and Rulership). All come with portraits and card art, and skills, support cards, and text are refreshed to the new patch.
  • Race engine: two skill conditions the newest skills use are now read from the real race instead of being skipped. One checks whether the uma got a good start; the other counts how many inherited unique skills she is carrying (the copies of a parent or grandparent's unique that a build brings into the race), so a skill gated on that count (連綿) fires when it should. These count whether or not they have been evolved into their rarer form.
  • Grandstand: a new per-uma debug overlay, off by default and toggled in settings, draws each uma's live race state beneath her chip. Colored status dots, with an on-screen legend and hover tooltips, show her lane movement and direction, the no-pass zone before the first corner, blocking, her position-keep mode (speed-up, overtake, pace-up, pace-up Ex, or pace-down), and when she is rushed, alongside an HP bar. It is a look under the hood at how the field engine is driving each uma.
v0.44.1
  • Grandstand: fixed the track orientation. The umas were running the wrong way around the course and the oval curved against the track's real handedness. Now right-handed courses (右回り, like Nakayama) start the umas moving left and loop clockwise, and left-handed courses (左回り, like Tokyo) start moving right and loop counterclockwise, matching real life and the game's camera. Race results are unaffected; this was purely how the track is drawn.
v0.44.0
  • New game data: updated to the latest JP patch, adding Fine Motion and Narita Top Road (with their skills and portraits) and refreshing skills, support cards, and text. A couple of the newest skills' effects are not simulated yet (their internal codes are brand new and not reverse-engineered); they show up but currently do nothing in the sim, and the rest of each uma's kit works normally.
  • Race engine: HP drain during the start dash now matches the real game. While an uma is still in her start dash the game pins the drain formula, burning a constant 20 HP per second (times condition and track modifiers) where the plain formula would burn almost nothing. Verified against per-frame race captures; both engines now burn roughly 10 to 15 more HP per race, which matters most for tight stamina builds.
  • Race engine: skill durations that scale with race state now do. A handful of uniques stretch their duration by remaining stamina (麗しき花信風, 爛然闊歩, きらめくは海、まばゆきは君, ごろりん！？パワードライブ), by distance behind the leader (113転び114起き), by how long you were boxed in mid-race (CHERRY☆スクランブル), or by uphills before the final corner (evolved 超常体験). These ran at base duration before; in the emulator they now read the real race state at the moment they fire.
  • Race engine: grow-per-event skills now grow per event in the emulator. Skills whose text says the effect increases up to N times (per overtake during the effect like 熱血！！風紀アタック and 究極テイオーステップ, or per skill fired during the effect like 火神鳴 and 夢の先へ、届け！) used to apply a fixed averaged value up front. They now start at the base value and gain each step when the overtake or skill activation actually happens; 熱血 also gains its +1 second of duration per overtake, up to 3 times.
  • Race engine: two value bonuses now check their real condition in the emulator. 叙情、旅路の果てに only gets its bigger boost when 20m or more behind the leader, and CHERRY☆スクランブル's strength scales with the longest mid-race box-in instead of always assuming a middling one.
  • Race engine: a recovery that lands after the late race begins now re-plans the last spurt. A heal in that window can raise the spurt speed and, if the uma has not started her spurt yet, move its start earlier, so late heals help stamina-tight umas the way they do in game. Debuffs never trigger a re-plan.
  • Single-uma sim: the last spurt now begins where the stamina plan says it can. The sim holds the late-race base pace and switches to spurt speed at the planned start position, the way the emulator already did, instead of jumping to spurt speed right at the late-race boundary.
  • Single-uma sim: comparing two umas now runs a full finish-time simulation for each and shows the two distributions (with per-skill バ身 values) side by side, replacing the old paired head-to-head gap histogram.
  • Settings: two new toggles for formulas the reverse-engineering community disagrees on: which Wisdom feeds part of the per-section speed randomness, and whether the downhill speed bonus reads the slope's sign or its steepness. Both default to the behavior the app already had.
v0.43.0
  • Race emulator: a new Received toggle in the playback controls (on by default, next to Skills) shows the buffs and debuffs each uma gets from other umas' skills, drawn on the affected uma in green for a buff or red for a debuff and set apart from its own skill activations. Turn it off in the controls for a cleaner view.
v0.42.1
  • Race report and corner-triggered skills: corner numbers are now correct on courses that start mid-loop or run multiple laps. The report was numbering corners 1, 2, 3 and up straight through (so Nakayama 3600 showed 1 to 8), and corner skills could target the wrong corner on those courses. They now follow the game's numbering, where the final turn is always corner 4 and the count works backward from there, so Nakayama 3600 reads 1, 2, 3, 4, 1, 2, 3, 4, and a race that opens on the back straight (like Arima 2500) correctly starts at corner 3.
v0.42.0
  • Race engine: unique skills whose second half boosts the all-out spurt at a random point in the Last Spurt (like Almond Eye's Peerless Heroine) now fire at a random point each race, instead of firing the instant the spurt starts every time. They were making those umas consistently stronger than in the real game and unfairly pushing front-runners down the order; now they vary race to race as they should.
  • Race engine: skills that trigger on a specific corner (like 型破り / Mold Breaker on the third corner) now fire on that corner instead of any random one, so their boost lands where the game places it.
  • Race engine: リード確保 (secure lead) now activates more often at high Wisdom, matching captured races; the old flat rate under-fired by roughly half at modern Wisdom. This is a calibrated stopgap until the exact formula is known.
  • Race engine: the last spurt now plans a shorter, faster final segment when stamina is tight (the documented speed-and-distance model), improving stamina accuracy for stamina-limited umas. No effect when an uma has stamina to spare.
  • Race engine: during the mid-race jostling, an uma that needs to conserve stamina now does so before joining a position-competition burst, matching the game's order. Mostly affects how often conserve shows in the report.
v0.41.0
  • Settings: new toggle for whether skill values in the race report include the Wit Limit Break (賢さ上限突破) boost. Off by default, so the report shows each skill's base value; turn it on to see the boosted value the engine applied.
  • Race engine: lead-distance skills like Billions of stars now scale by the lead you actually built by the two-thirds mark (under 10m, under 25m, or 25m and over), instead of always assuming the biggest tier.
  • Race engine: the position condition (順位率 / order_rate) now rounds to the nearest place in single-uma runs too. Skills gated on your position (for example order_rate over 50 needing 6th or worse in a 9-uma race) now trigger at the same place the field sim and the game use.
  • Race engine: 脚を貯める (conserve power) now uses base Power before the over-1200 halving and without the surface modifier, matching the documented formula. High-power umas get a slightly larger burst, and it no longer drops on dirt.
  • Race engine: smaller skill-value fixes. The highest-stat value bonus now reads raw stats instead of course-adjusted ones, and straight-line skills pick one of the course's straights with equal chance rather than favoring the longest.
v0.40.1
  • Race engine: fixed the 距離差割合 (distance_diff_rate) skill condition. It measures your position in the pack between the lead uma and the last uma, as a percentage, but was being scaled against the whole course length instead of the front-to-back gap, so it almost never matched its thresholds. Because of that, some 追込 last-spurt skills (like 仕掛け抜群) never activated, while some front-of-pack skills activated regardless of position. They now trigger based on your actual position in the field.
v0.40.0
  • New Saved umas tab in Builds: import whole opponent teams from captured or shared race replays (load many files at once), grouped by trainer, with duplicate teams skipped. Flag the teams you want to use as opponents, and filter or search the list.
  • Grandstand: a new Race set button next to Race! runs many races at once and aggregates the results (it replaces the old batch button in the results panel). It can fill the other slots with random opponents drawn from your saved teams, keeping each captured team together, never repeating a trainer in one race, and racing them at max mood.
  • Race set report: a Top opponents section ranks the opponents you faced, and an All teams faced section shows your head-to-head record against each team (your win and podium rate, their win rate). The trainer name shows under each uma, and you can watch any single race to replay it with its exact opponents, then inspect or edit them like a normal setup. Both sections are collapsible.
  • Clarified the win and podium pie charts: they show each uma's share of all wins or podiums in the set, while the cards show each uma's own rate. A uma with a 50% podium rate is about 17% of the pie because there are 3 podium spots per race.
v0.39.1
  • Race report: 追い比べ (duels) now show for every uma that actually dueled. Before, a uma still dueling as it crossed the finish line was never recorded, so a duel between two umas could look like only one of them dueled. Duels that run all the way to the line, and 3 or more way duels, now all show correctly. The engine also now guarantees a duel always activates for both umas, never just one.
v0.39.0
  • Race report: added a Stat boosts section. For each uma it lists the green (passive stat) skills that activated and the exact stat each one added, like 先行のコツ○ giving 賢さ +40, so you can confirm your greens landed and check skills that scale with them.
  • Race engine: green skills that bundle a small secondary effect, such as the コツ skills, now count as green skills. This matters for skills that scale with how many green skills activated, like the unique 理運開かりて翔る. Before, those greens were skipped, so the bonus could come out one tier too low. The small field-of-view part of コツ skills is still not modeled.
  • Grandstand: tidied the controls at the top. The setup selects and option toggles stay on the left, the Entrants, Presets, Load replay, Share, Spoiler-free, and Reset buttons share one row, and the big Race! button is on the right.
  • Grandstand: the minimap now slides aside when the Order sidebar is open, so it stays visible instead of sitting behind it.
v0.38.0
  • Grandstand results table redesign. Each key race mechanic (掛かり, 追い比べ, 温存, バテ) now has its own column showing where on the track it happened and for how long, instead of a strip of indicators along the bottom. The top three finishers get gold, silver, and bronze styling, the mood and running-style chips are tidier, the skills button sits next to the name, and 'Pop' is now 'Fav' (favorite, not popularity).
  • Running-style tags (逃げ, 先行, 差し, 追込, 大逃げ) now use the in-game colors everywhere they appear.
  • Race X times: the 'Each race' list was rebuilt into cleaner cards that line up properly, and you can reopen the batch results after closing the dialog with the Batch results button.
  • The live Order list is now a sidebar inside the race view on desktop. It opens by default and slides in and out from a tab on its right edge, and no longer takes up space on mobile.
  • The race view is resizable on desktop: drag its bottom edge to make it taller, its right edge to make it narrower, or double-click a handle to reset. The entrants list grows to match.
  • Added a fullscreen button to the race view (top left) that puts the track, playback controls, and Order list on the whole screen. Press Escape to exit.
  • Track drawing is cleaner on long and circuit races. Laps that cover the same ground more than once no longer show doubled rails or tangled lane lines, and lane gridlines now appear around the field rather than across the whole track.
  • Fit view zooms out much further, so a whole corner (or the whole track) fits on screen.
  • Popups now open and close with a small animation.
v0.37.3
  • Grandstand: the closest finishes now read as ハナ (nose) instead of 同着 (dead heat). The game never produces a dead heat, so the smallest possible margin is a nose.
  • Updated the Information and caveats notes: a clearer Load replay description, a more precise power-conserve caveat, and a line to report any mistakes on Discord (nostux).
v0.37.2
  • Race report: the Oikurabe opponents shown for a uma are now accurate. Before, the list was a best guess (the umas closest on average during the duel, which could include one that was just passing by). Now it lists the umas you actually dueled, matched by who was dueling at the same time and stayed within duel range of you. This builds on the duel fix and works for both simulated races and loaded replays.
v0.37.1
  • Grandstand: fixed 追い比べ (the final-straight duels) so both umas in a duel get the boost, not just one. The trigger was checking each uma's own placement against the top half of the field, which made a duel between a higher- and a lower-placed uma fire for only the higher one, and missed duels between two lower-placed umas entirely. Now a duel starts as long as one of the pair is in the top half, and both umas duel together. Checked against 20 captured Tokyo 2400 races, where every real duel fires for both umas.
v0.37.0
  • Added a Settings dialog, opened from the gear next to the language toggle. Its first option forces skill, uma, and course names into Japanese or English regardless of the site language (or leave it on Auto to follow the site language). The choice applies everywhere, including the skill labels on the track during a race, and is remembered on your device.
  • Race X times report: each uma now shows its oikurabe (追い比べ) rate, the share of races where it got into a duel, in place of the popularity number.
v0.36.0
  • Race report: added a Buffs received section, the positive counterpart to Debuffs received. When another uma buffs this one (an ally buff like ルミナス・スペクトラム, ムジカ・シンティッランテ, or ドーノ・ディ・フローラ！), it shows here marked with the speed skill icon, with who cast it and where on the track. Hovering a bar shows the exact value and duration that landed, and the Debuffs received bars now show that detail too. Buffs you cast on yourself stay in your own activation list as before.
v0.35.2
  • Race engine: the resonance skills コネクト and "METI"レゾナンス now activate the linked シンパシー for every uma carrying it, even when fewer than five do. Before, these only applied their own speed boost and never set off the シンパシー they reference, so it stayed inactive unless five or more umas already carried it.
v0.35.1
  • Loaded team replays now show each uma's real team. The team was being guessed from gate position (every third gate a new team), which scrambled the teams in races where a player's umas start from spread-out gates. Each uma now keeps its captured gate and shows its correct team.
v0.35.0
  • Skill names now follow your language everywhere. Some places (the race report's activation list, the skill picker, the chart labels, and the floating names on the track during playback) were stuck showing Japanese, or showing both languages at once, regardless of the toggle. They all respect the EN / JA setting now.
  • Skills are clickable for their description everywhere they appear. Click a skill's icon or name (in the build editor, the deck builder, support-card lists, recommended sets, the race reports, and more) to open its conditions and effects. Places where a click already does something, like adding a skill in the picker, are unchanged.
v0.34.0
  • Japanese now covers the whole app. The home page, the About page, the data dictionary tabs and overview, and a couple of menu tooltips were still showing English even with Japanese selected; they now follow the language toggle like everything else.
  • Reordered the tools menu: Grandstand is first, then Race Simulator, Builds, and the Data Dictionary. The planned Skill-proc Simulator entry was removed.
  • Grandstand: Randomize gates is on by default now.
  • Tidied the page headers: the big title under the logo is gone on each tool page, since the page name already shows next to the Umalytics logo.
v0.33.0
  • Grandstand: movement is properly smooth now. The camera was easing per frame instead of by real time, so it could stutter and behaved differently on high refresh rate screens; it now tracks real time. The umas are also curve-interpolated between simulation frames, so they glide instead of stepping. This is display only and does not change race results.
  • Grandstand: following an uma (by clicking it) now keeps the camera locked on it at any playback speed. Before, the faster the playback, the further the camera fell behind.
  • Grandstand: the Fit view is more zoomed in. It frames the field to fill the view instead of leaving a wide empty border, while still keeping everyone on screen.
  • Grandstand: the uma circles are sized to the lane grid (just over one lane wide) and scale smoothly across zoom levels, staying a bit larger when zoomed out so they remain easy to see.
v0.32.0
  • Updated to the latest game patch: refreshed skills, characters, and support-card data, and added the new uma カレンブーケドール (Curren Bouquetd'or) with her portrait.
  • Added her evolved skill 想い束ね、前へ, which surges you forward when the most popular uma uses a skill at the final corner of a medium or long race. This needed a new activation condition the engine did not handle before.
v0.31.0
  • Skills whose effect strength changes by condition now use their real values. About 48 skills carry a hidden value modifier in the game data that we were not reading, so they applied only their base number. This is now decoded, so for example 灰の光跡：シンデレラグレイ gives 0.55 on the Arima Kinen course and 0.45 in a mile race (not a flat 0.35), アオハル and 叡智 / 加護 use their boosted values, Peerless Heroine reaches its 0.65 on mid, and speed or stat scaled skills like 夏空ハレーション and 限界の先へ scale with your uma.
  • The race simulator's two 'scenario skills at max' toggles no longer do anything, because the real per-skill scaling above is now applied automatically. They will be removed in a later update.
v0.30.0
  • Skills: combo skills whose second half chains off their first (for example コール&レスポンス, 黄金を訪ねて, Queen's Rebirth) now only fire that second half if the first half actually fired. Before, the second half could trigger off any skill, so a dirt-only skill's follow-up could go off on turf. This affects every skill with a chained second effect.
  • Replays: loading a captured replay now detects whether the race was turf or dirt and draws it on a course of the right surface. Replays carry no surface, so a dirt race used to be shown on a same-distance turf course, which silently switched off every dirt skill (and vice versa). The track picker is also limited to the detected surface.
  • Grandstand: the track now only draws the lanes that are actually raced in. The outer part of the course that no field ever reaches (most of the width on a small field) is no longer drawn, so there is far less empty space and visual noise.
  • Race report: the Debuffs received section now uses the debuff skill icon instead of a plain down arrow.
v0.29.1
  • Fixed the Del Mar and Santa Anita courses, which were loading about ten times too wide (a huge number of lanes). On those tracks a front runner with 危険回避 could drift out to lanes that do not exist in a real race. They now use the correct track width.
  • 危険回避 and シックスセンス now pull the uma to the correct lane (the outermost lane of a standard field) on every course, instead of moving further out the wider the track is. Checked against race replays across Del Mar, Tokyo, Niigata, and the 1200m sprints.
v0.29.0
  • Grandstand: in the progress bar above the track, the uma markers now keep a readable minimum size, and an uma that falls far behind (a debuffer or a weak runner) is pinned to the back of the bar instead of squeezing the whole field tiny.
  • Skills: several skills that previously never activated, or quietly lost part of their effect, now work. This covers 煌星のヴォードヴィル and 絶対は、ボクだ, the 聖女 skills (無垢の祈り・ホーリーライト, 覚醒せし聖女, 天与の恩寵), and passives that bundle a stat boost with another effect (荒磯好みの黄金船, コネクト, the コツ skills, and the ヒーロー skills), whose stat boost was being dropped.
  • Skills: corner skills such as 弧線のプロフェッサー and コーナー巧者 / コーナー加速 (and their evolved forms) can now activate more than once in a race on long, multi-corner courses, the way they do in game. Each activation is still limited by the skill's cooldown.
v0.28.1
  • The current page name now shows in the top bar next to the logo (for example Umalytics / Grandstand), so it is always clear which tool you are on.
  • Grandstand: the uma circles on the track now also grow as you zoom out, up to a sensible maximum, so the field stays visible on the wide view instead of shrinking to dots. Zooming in still tracks one horse length as before.
v0.28.0
  • Grandstand: the markers in the progress bar above the track are now drawn one バ身 (horse length) long, so the gaps between them read as real margins. The bar also starts pinned to the START line and finishes pinned to the GOAL line, opening out to follow the pack in between.
  • Grandstand: the uma circles on the track scale with zoom again, but can no longer shrink below one horse length once you are zoomed in.
  • Grandstand: the bottom-left placement readout now shows at most your first three umas (Team 1).
  • Grandstand: smoother movement around the track. The course path is denoised and curve-interpolated so umas in the outer lanes no longer wobble. This is display only and does not change race results.
v0.27.1
  • Japanese is now complete across the app. The Builds tool, the Support Cards page, and several race screens still had English text for JP players; those are now fully translated.
  • Japanese terminology now matches the game: バ場 for track condition, バ身 for race margins, 賢さ判定 / 発動率 for the skill activation check, and 掛かり for the rush state, plus assorted consistency fixes.
v0.27.0
  • New name and look. The site is now Umalytics, and the race emulator is now Grandstand (full name Umamusume Grandstand). Fresh logo to match: a U cradling a small rising chart.
  • Race simulator: the head-to-head comparison (two umas, bashin histogram) has been retired, now that Grandstand plays out full multi-uma races.
  • Race simulator: position-keep speed-up (a front runner pushing to open a lead) is off by default now, with a toggle in the position-keeping settings if you want it. Grandstand still models it as part of the real race.
v0.26.2
  • Saved builds now keep the uma's portrait. It shows in the Skill presets & builds list and loads with the build. Older saved builds get their portrait back too, matched by the uma's unique skill, so you do not need to re-save them.
  • Swapping the character in the entrant editor now keeps the running style you picked (it only loads the uma's style into an empty slot), and replaces only that uma's own innate (pink) skills. Generic gold evolved skills and anything you added by hand are kept.
  • The race results now show each uma's running style.
  • New umas default to the best condition (絶好調).
  • Fixed entrant rows squishing while you drag to reorder them.
  • Tidied the uma detail (ウマ娘詳細) popup: the rank and score sit next to the name with the running style on the right, and the aptitude rows are labelled バ場適性 / 距離適性 / 脚質適性.
v0.26.1
  • Loaded replays now work out each uma's rank using her real unique-skill level from the capture, instead of assuming the unique is maxed. A uma whose unique was not at level 6 could previously show one rank tier too high. Applies to newly captured replays.
v0.26.0
  • Race report: hovering a skill's activation bar now shows how long it actually lasted this race in seconds, plus the real effect it applied, like +0.45 m/s or +4.5% HP. Every modifier is already worked in: the skill's level, scenario value boosts, and the Wit limit break bonus.
  • Opening a skill's details now shows its duration for the current track, instead of only the base value with a note that it scales with distance.
  • Fixed Chrono Genesis's ultimate. It doubles the duration of her own evolved (awakening) skills in medium and long races, but it was also doubling ordinary gold evolved skills that any uma can carry. Now only her own innate evolves are doubled, as in the game.
  • Circulating Love now scales its speed boost with fan count, using a fixed reference fan count for now, so its value and duration read correctly.
v0.25.0
  • New Builds tool. Set a 6-card support deck like the game and instantly see every skill it makes available: each card's gold (event) skills and its white hint pool, with a badge showing how many of your cards can hint each one. Click a skill in the pool to add it to your build, or search the whole skill list to add any skill by hand. The white and gold version of a skill replace each other, so you never hold both.
  • Save, load, rename and delete builds, and export or import one as a shareable code.
  • New Support Cards page under Data: browse every support card with its artwork, type, rarity, the golds it gives, and its hint pool.
  • Support cards show their real in-game art. Small previews load instantly in the app, and the full-resolution card art loads on demand.
v0.24.0
  • Each uma now shows its overall rank (評価点) using the game's own rank glyphs, from G up through the SS and over-cap U / L ranks. It is worked out from the uma's stats, skills and aptitudes and appears in the build editor (live as you edit), on the race entrant cards, in the uma detail popup, in the race results, and in the 'Race X times' report.
  • The rank is matched to the real game: the full rank ladder was checked against captured race data (9 real builds, all exact), and the score curve was calibrated against in-game values, including stats above 2000 (which the reference data had been cutting off).
  • Fixed skills that fire a second time during a race. Some skills (like Peerless Heroine) burst again 'somewhere during the spurt' when another skill activates, but they were only ever triggering at their first point. They now fire both times, as in the game. This affected 26 skills, including several character uniques and common gold skills.
v0.23.1
  • Importing a uma now still finds her even when the outfit name has a wrong or misread character (a common OCR slip, like 喊 vs 威). When the bare name fits more than one uma, it picks the right one using the unique skill in the line.
v0.23.0
  • You can now add evolved (pink) skills to a build by hand. Only a uma's own base unique stays off the picker, since you get that by loading her.
  • Importing a uma from a pasted line now recognizes who she is from the name, so it loads her portrait and her own (non-inherited) unique skill instead of a generic one.
  • On import, a skill whose name is shared by an inherited version and an evolved version (like 黄金を訪ねて) now comes in as the evolved version, which is the usual case.
  • Loading a saved build, or a build from Skill presets & builds, now shows the uma's portrait. The saved-builds list also shows each uma's icon instead of a generic person.
  • When a loaded replay's distance matches several tracks, the 'Which course?' picker now tints each option green for turf or brown for dirt.
v0.22.0
  • The sidebar is now an overlay drawer on every screen: it slides over the page with a dimmed, blurred backdrop instead of pushing the content aside, and it is restyled to match the rest of the app (raised pills, the current page shown as a white highlighted card).
  • Race emulator entrant cards are redesigned: the uma's portrait is now large on the left, with the name, gate, team, running style and popularity laid out beside it, and View / Edit / Remove as compact controls (Remove moved to the top-right corner).
  • New 'No team' option for an entrant in Teams mode: that uma races with no teammates, so team-based skills skip it. The 'Teams' toggle is renamed 'Enable teams'.
  • Gate and team markers are now easy to tell apart (a muted square gate number vs a solid colored team circle), and dragging an entrant to reorder settles in place instead of snapping back to its old spot.
  • Emulator layout: before a race the track now fills the width instead of leaving an empty column, and the toolbar's action buttons are grouped together on the right.
v0.21.0
  • New Lanes toggle on the track draws the lane gridlines, so you can see which lane each uma is running in.
  • Mob umas in loaded replays now show their real in-game name when they have one, or 'Mob N' otherwise, instead of a generic label.
  • The race report now shows each uma's icon next to its activated-skills count, and the Oikurabe (追い比べ) opponents section uses the guts stat icon.
  • Straight sprint courses like Niigata 1000m now line the field up on the correct side of the track and hold their lane through the race, instead of drifting across the empty lanes. This matches what the captured races show.
  • Fixed front-runner mobs being too strong in the opening stretch. The x2 emergency catch-up burst a nige or senko uses when it falls out of position (pace up Ex) was lasting too long; it now runs for one section like every other position-keep mode, then re-checks. Early-race order and pace line up much closer to real races now, and a strong senko or nige build beats weak front-runner mobs the way it should.
v0.20.0
  • More skills now activate in the race emulator, read from the real field: Straight Course (直線コース) on no-corner tracks; Loner (おひとり様), Competitive Spirit (対抗意識) and Introverted (引っ込み思案) from how many rivals share your running style; Eyes On You (徹底マーク) when the favorite runs your style; and Connection (コネクト) when another uma in the race carries its paired skill.
  • Graded Exchange Races (交流重賞) skills apply at the local exchange-race tracks (Kawasaki, Funabashi, Morioka, Ooi); Tight Turns (小回り) at the short-circuit tracks (Sapporo, Hakodate, Fukushima, Kokura, Kawasaki, Funabashi); and overseas skills at Longchamp, Santa Anita and Del Mar.
  • Charisma skills that need a specific character in the race now check the field, and fan-count skills assume a trained uma's fan base.
  • These were previously silent (they could never meet their conditions). Some skills are still not modeled, mostly vision skills and a few that need race grade or night races.
v0.19.0
  • You can now share a 'Race X times' report: hit Share in the report to copy a link, and whoever opens it sees the same results and can dig into the same races.
  • From the race list in the report, Watch replays any single race in full on the track, so you can see exactly how a given result played out.
  • The last report stays in memory: a new 'Last results' button in the results reopens it without re-running. Running another batch (or opening a shared one) replaces it.
v0.18.0
  • New 'Race X times' button in the results (replaces 'Race again'): run up to 500 races at once, off-screen with no playback, and get a report.
  • The report has win and podium pie charts, a card per uma with its win rate, podium rate, average finish, out-of-HP rate, kakari rate and more, and a race-by-race list you can expand to see each finish.
  • Each uma is shown in its own theme colour (from U-tools), with the character icon on the pie sized to its share.
  • Mobs are kept out of the per-uma stats since a fresh mob fills each spot every race. They show as one combined slice and as 'Mob slot N' in the race list.
  • Added U-tools to the credits, for the character colours and for cross-validation.
v0.17.0
  • Race popularity (人気) is now worked out for each uma from its stats, instead of everyone being treated as the top favorite. Guts and Wit weigh in the most, and it is relative to the field, matching the game. This makes the favorite-only and underdog-only skills fire correctly.
  • Popularity shows in the results as its own column, and next to each uma in the entrants list when the field is fully set.
  • More skills now work: gate skills (Concentration, Focus, Gate Trouble) now change the start delay; Great Escape now makes a front runner run as 大逃げ, building a much bigger early lead before fading; and the kakari skills (Favorite for reals?!, Self-control, Hyper Excited) now change how likely an uma is to rush.
  • New Randomize mood toggle, like Randomize gates: each race rolls every uma a random condition (調子), the way competitive races do, so popularity and results vary race to race. Off by default.
  • Results table cleanup: added column headers, a mood (調子) badge for each uma, and capped long skill lists with an 'and N more' link.
v0.16.0
  • Race emulator mobs now better match the game's competitive-event fillers (chanmi, LoH). Their stats cap at 1000, they get A for the race's distance, surface and running style, and they carry skills drawn from real captured races. They also vary in running style and aptitude instead of all coming out as front-runners. This is a close approximation, not an exact copy of the game's mobs.
  • Race presets can now be exported to a file and imported back, for backups or sharing.
  • Shared race links now carry all the settings with them, so teams, randomize gates, auto seed and the rest open the same way for whoever you share with.
  • Mobile fixes: search boxes and pickers now close when you tap outside them, the search field resets each time you reopen one, and the sidebar closes after you pick a page.
  • More skills now work in the simulation, checked against captured races: lane-change skills like Clever Step now fire when the uma actually changes lanes, and slope skills like After-school Magical Girl and To where the heart beckons now activate on shallow-slope courses such as Hanshin 2200m.
  • Inner-lane skills (King of the Castle, Inner Experience, Incinerating Blade, Golshi Warp, Ceremonial Fan Dance, Guilty, Christmas Miracle, Good Luck Experience) now activate on their other conditions. The inner-lane check itself is on a workaround for now: we assume it is met, so these can activate a little more readily than in the game until we have capture data to model it properly.
  • Fixed a harmless console error from the entrants list on page load.
v0.15.2
  • Fixed umas instantly dropping to minimum speed the moment they run out of HP. They now slow down gradually, like in the game. (The instant drop was a real in-game bug at 5th anniversary, but it was patched out soon after.)
v0.15.1
  • Fixed a uma's own unique skill sometimes failing its activation check. Unique skills now always activate once their condition is met, like in the game. Inherited and evolved skills still roll as before.
v0.15.0
  • Skill details now show the debuffs an uma was hit by, like the game's post-race screen, so you can see where you lost speed or stamina to a rival. They show only in the details, not as icons in the results preview.
  • Inside and outside gate skills now use the bracket number like the game, not the raw gate. In fields bigger than eight umas the outer brackets hold more than one gate, so for example gate 6 of 12 no longer counts as an outer gate. This also fixes the Lucky Seven skills.
  • More skills now work in the simulation: Trick (Back), Guten Appetit, and the per-furlong skills.
  • Fixed Adventure of 564 not setting off a gold skill whose own condition the race did not meet.
  • Loading a replay only asks which course when the distance is ambiguous, then offers the likely distances.
v0.14.0
  • Race emulator: a Randomize gates tickbox. Each race shuffles which gate every uma starts in (your team and builds stay the same).
  • More skills now work in the simulation, checked against real captured races:
  • Danger Avoidance and Six Sense now move the uma toward the middle of the track early on.
  • Position Sense, Aoharu Ignition Wit and similar lane-move skills now give the small speed gain from changing lanes.
  • Restrained and Faltering style debuffs (けん制 / ためらい) now slow or drain the rival running styles they target. Your own team is immune.
  • Adventure of 564 now sets off random gold skills mid-race, like in game.
v0.13.0
  • Opening a shared race link now shows a loading screen and blocks input until the race is ready.
  • When a race starts it scrolls into view and takes focus, so on mobile you can see that it began.
  • Press the spacebar to play or pause the race.
  • Clicking the timeline now jumps to that point without pausing. Only dragging it pauses.
  • Fixed pressing Race and then spacebar sometimes restarting the race.
  • Wider entrants list so long names are no longer cut off.
  • Japanese text fixes and translations across the info section, the about page, and several buttons.
v0.12.0
  • Teams mode: an uma's team is now separate from its gate. Pick the team with the colored chip and drag to set gates, so your team (the one shown in the score) can start from any gates.
v0.11.0
  • Race results: every uma now has its own Skill details button, and the result rows line up in clean columns.
  • Entrants can be reordered by dragging the handle next to each gate.
  • Fixed simulated races showing the same wrong finish time for every uma.
  • Finish times and margins in simulated races now use the model verified against real captured races.
v0.10.0
  • Race emulator: a Share button that copies a link to the current race, simulated or real. Opening the link plays the same race.
  • Shared real replays play without the capture disclaimers, and replays are stored encrypted so they cannot be scraped in bulk.
v0.9.3
  • Japanese now uses バ身 instead of 馬身 for race margins, matching the game.
v0.9.2
  • Japanese now uses 編成 instead of ビルド for builds.
  • Added this changelog so you can see what changed in each version.
v0.9.1
  • Race result list: click a uma to open her full skill details (with a clearer cue).
  • Race result list: gate numbers now use the JRA frame colors, matching the rest of the sim.
v0.9.0
  • Race emulator: live team positions shown at the bottom left during the race, like the game.
  • Race emulator: a big Race button, and phase markers on the top timeline showing when each race phase starts.
  • Race emulator: a what-is-a-replay help note and an information and caveats section.
  • Race emulator: the Sympathy and レースの真髄・賢 skills now work.
  • Cleaner home page and side menu, and more consistent skill wording across the app.
  • About page now shows the app version and contact info.

Umamusume: Pretty Derby and all related names, data, and artwork are © Cygames, Inc. This is an unofficial fan project with no affiliation. If you're a rights holder and would like something removed, please reach out at nostuxi@gmail.com or on Discord (nostux).

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