Breeding Tool

DOC Breeder Studio

Plan your Derby Owners Club stable: every horse, every version, breed & compare in your browser.

Launch the Studio No download, runs offline · ← back to the game

Derby Owners Club hides a deep breeding game behind the betting window. DOC Breeder Studio opens it up: look up any CPU horse, understand what it actually does on the track, and test a pairing before you commit. It's a free fan tool, nothing to install, and your picks never leave your browser.

Three ways to use it

Foal Calculator — pick a sire and a dam and see the projected foal's stats. Narrow the lists with filters (stamina/speed/sharp, dirt aptitude, ability grades).

Horse Analyzer — choose any horse to see its surface, distance, running style, standout abilities, stat bars and ability grades at a glance.

Breed & Compare — line up a sire and a dam side by side and project the foal: inherited stats, ability inheritance table, and a likely distance range.

What makes it accurate

All four versions: DOC 2000 & DOC '99 (Japanese), plus World Edition (Rev C) and EX (Rev D).
ROM-verified data: every horse's stats are read straight from the arcade program ROMs, not guessed.
Japanese names in katakana: the Japanese versions show each horse as カタカナ (English).
Readable profiles: surface (Turf / All-Surface / Dirt), distance (Sprinter / Miler / Stayer), running style (Front-runner / Start dash / Last spurt / Stretch-runner / Almighty, estimated from the breeding bands with the game's own style rule), and standout traits like Gate Demon or Closing Kick.

How to read a horse

Internal stats (Speed, Stamina, Sharp) sit on a roughly 0–60 scale; the AC bar is the horse's dirt aptitude on a 0–255 scale. The four ability grades go ◎ (great) → ○ (good) → △ (fair) → ✕ (weak), the game's breeding symbols (✕ 1-4, △ 5-8, ○ 9-12, ◎ 13-16). On World Edition a horse's symbols are fixed at birth; racing, training and retiring never change them. (DOC 2000 is different: when a card is read to play, the game adds up its six marks, ◎ = 3, ○ = 2, △ = 1, ✕ = 0, and at 14 points or more every mark drops one step, the Ver.2 rule Japanese players recorded (a horse that has a ✕ instead gets that ✕ raised to ○ and its other marks dropped two steps); a retired card read as a breeding parent gets the same check at 15 points, and the lowered marks are saved back to the card.) A foal's dirt aptitude is the rounded-down average of each half of its parents' dirt ratings, taken separately. At a World Edition cabinet, from a horse's 11th breeding on, its foals are made from a weakened copy of it (stats 2 to 5 lower, symbols 1 or 2 lower) while its own card never changes; the catalog horses in the Studio never wear down. Tap any tag in the tool for a one-line explanation.

Tip: a Two-◎ stock tag means the horse has two or more ◎ breeding symbols, strong stock to pass on (about half of the catalog has it). Not the same as the arcade's Blue Chip seal, which grades birth internals.