# Touhou reconstructions: an agent-driven method across three games

> An essay published on REA’s site, with pinned evidence notes, describes one author’s agent-driven reconstructions of TH08, TH095 and TH04. It dates milestones from public commits and progress ledgers, separates exact-comparison and playable-build oracles, and documents a TH08 check that missed wrong floating-literal data. Project results remain author-reported, and REA is credited with supplying analysis evidence, not the reconstructions themselves.

- Type: Case study
- Targets: Binary · Game
- Category: Official REA: case studies
- Relationship: Official REA case study
- Sources reviewed: 2026-10-18
- Added to the catalog: 2026-10-18
- Original resource: <https://rea.tools/blog/touhou-reconstruction/>
- Primary source: <https://github.com/morluto/rea/blob/c12d9eda87aa5a022ee7e18ea96d8d03bfd12e96/website/evidence/touhou-reconstruction-method.md>
- Catalog page: <https://awesomerea.org/resources/rea-touhou-reconstruction-method-case/>
- Record JSON: <https://awesomerea.org/resources/rea-touhou-reconstruction-method-case/record.json>
- Chinese version: [简体中文](https://awesomerea.org/zh/resources/rea-touhou-reconstruction-method-case/index.md)

## Requirements & limits

- **Prerequisites:** The essay and notes supply no game files, compilers or builds; each project’s repository documents its own original-game and toolchain requirements, and game rights stay with their owners. GensokyoClub’s TH08 history keeps its attribution and license.
- **Scope:** The evidence notes, checked on 10 October 2026, treat three separate projects: a continuation of GensokyoClub’s TH08 1.00d reconstruction, a TH095 1.02a reconstruction started from zero confirmed functions, and a PC-98 TH04 reconstruction crediting ReC98. Milestone intervals use public commit timestamps and measure recorded spacing.
- **Testing evidence:** Pinned ledgers report 1,106 of 1,107 TH08 functions accepted, 696 exact TH095 functions out of 697 confirmed, and 661 exact TH04 functions out of 663 reviewed candidates, each under its own definitions; the notes warn against cross-game rates or whole-executable completion percentages. TH08 Linux and Web ports, a playable TH095 Windows i386 build and four TH04 DOS products are recorded milestones. TH04 play results rest on the maintainer’s manual observations, and its 64-bit port is in development.
- **Testing evidence:** In TH08, an instruction-byte comparison accepted source using 0.0 where the original executable used 128.0, because it did not check the referenced literal data. TH08 PRs #11 and #13 added literal-data checks and corrected twelve more stale references among 1,548 audited.
- **Attribution:** REA is described as supplying analysis evidence to agents; the projects also used their own analysis bridges and tooling. The author presents the method and its industrial analogy as an account and argument.

## Primary sources

1. <https://github.com/morluto/rea/blob/c12d9eda87aa5a022ee7e18ea96d8d03bfd12e96/website/evidence/touhou-reconstruction-method.md>
2. <https://github.com/morluto/rea/blob/c12d9eda87aa5a022ee7e18ea96d8d03bfd12e96/website/public/blog/touhou-reconstruction/index.html>
3. <https://github.com/morluto/rea/pull/1475>
4. <https://github.com/N0zoM1z0/th08/issues/10>
5. <https://github.com/N0zoM1z0/th08/pull/11>
6. <https://github.com/N0zoM1z0/th08/pull/13>

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## About this entry

The description was reviewed against primary sources.
Original editorial content: MIT. Linked projects, papers and assets retain their own rights and licenses.