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.

v0.37.0
  • 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).

Umalytics v0.37.0