Structured data on Japanese baseball in English: the amateur pipeline that feeds NPB, and the NPB players who could reach MLB.
Japanese amateur baseball produces hundreds of professional players every year, and a handful of them eventually reach MLB — Shohei Ohtani, Yoshinobu Yamamoto, Roki Sasaki and Yusei Kikuchi were all amateurs in Japan first. Almost none of that pipeline is documented in English.
This repository is the data layer. The written analysis lives at Japan Prospect Lab.
| Directory | Contents |
|---|---|
players/ |
One directory per player: game logs, profile, OOTP conversion |
ootp/ |
Out of the Park Baseball roster data. Free, always |
boards/ |
Ranked boards. 2026 NPB draft board and the NPB to MLB posting board |
reference/ |
League level equivalencies, unit conversions, school name mappings |
Start with reference/league-levels.csv if you have never tried to place Japanese amateur baseball on a scale you recognize.
Two boards are live. 2026 NPB Draft Board (18 players, ranked) has a written version with scouting notes. NPB to MLB Posting Board tracks which NPB players can reach MLB and how, with the eligibility rules explained - posting requires club consent and has no service time requirement, which is the most common misunderstanding in English coverage.
- High school — Koshien and the prefectural tournaments
- University — Tokyo Big6, Tohto, and the regional leagues
- Corporate leagues (shakaijin) — company teams, the Intercity Tournament
- Independent leagues — Shikoku Island League plus, BC League, Kyushu Asia League
- NPB farm clubs — Oisix Niigata, Hayate Shizuoka
That last pair of categories is the part nobody else covers in English. You can watch Koshien on television. Almost no one is systematically tracking a 21-year-old right-hander in the Shikoku Island League who is throwing 94 and might be an NPB draft pick in two years.
Every game-log row carries a verified column:
| Value | Meaning |
|---|---|
verified |
Confirmed against tournament records and/or two or more independent outlets |
partial |
Event confirmed, but some stat fields were never published. Empty cells are empty, not zero |
reported |
Single secondary source only, could not be corroborated. Excluded from every aggregate |
Velocities appear in both km/h (as published in Japan) and mph. Heights and weights appear in both metric and imperial. Anything estimated rather than published carries an _est suffix and an explanation.
Full rules: METHODOLOGY.md
No spin rates, no release points, no batted-ball data. None of it exists publicly for Japanese amateur baseball. Anyone publishing those numbers is inventing them.
- Japanese amateur baseball has no single official statistical database. Coverage is incomplete by nature, and always will be.
- Japanese stadium radar guns are not calibrated to MLB Statcast and tend to run optimistic relative to TrackMan. Shade velocity down a mph or two when comparing to MLB data.
- Scouting grades are Japan Prospect Lab's own evaluation. They are not sourced from any MLB or NPB organization.
- Level equivalencies in
reference/are judgment calls, not measurements. They carry an explicit confidence rating.
Japanese amateurs are not eligible for the MLB draft. They enter the NPB draft, held every October. Players reach MLB later through the posting system (with their club's consent) or through international free agency after nine years of NPB service. A small but growing number now skip the NPB draft entirely and sign directly with MLB organizations as international amateurs — Shotaro Morii did it out of high school in 2025.
CC BY 4.0 — use it for anything, including commercially. Just credit Japan Prospect Lab and link back.
Corrections are welcome. Open an issue with a source. Accuracy matters more here than volume, and a documented correction is worth more than a new row.