By Galo S Mirth
Tanase Shogi (棚瀬将棋) is one of the important bridge engines in computer-shogi history. It came from the same development lineage as Tōdai Shogi, but it represented a rebuild by programmer Yasushi Tanase (棚瀬寧). In the late 2000s, it was strong enough to sit near the top of major computer-shogi events and became a familiar benchmark in conversations about practical, tournament-ready engine strength.
From Tōdai Shogi to a Rebuilt Engine
Japanese sources on Tōdai Shogi describe two major engine lines: IS Shogi and Tanase Shogi. The same sources identify 棚瀬寧 as the author and explain that Tanase Shogi was a fresh rewrite rather than a small patch. That context matters. In computer shogi, large rewrites often reflect a shift in search design, evaluation priorities, and time-management philosophy.
This is one reason Tanase Shogi is remembered: it was not only a product name attached to commercial releases, but also a competitive engine identity that appeared clearly in tournament records.
Competitive Results and the Era Around It
The World Computer Shogi Championship (WCSC) tables listed in Japanese references show Tanase Shogi as a top-class entrant in the 2007 and 2008 period, including second-place finishes in those years. In practical terms, this places it in the same competitive neighborhood as engines that defined the post-Bonanza acceleration era.
It also appears in period summaries of top commercial and tournament engines. For readers today, this helps explain why Tanase Shogi appears repeatedly in late-2000s software comparisons and exhibition discussions, even when it was not always the headline winner.
Tanase Shogi in the Denōsen Atmosphere
In Japanese coverage of the Denōsen years, the spotlight naturally fell on names like Ponanza, GPS Shogi, and Tsutsukana. Even so, Tanase Shogi remained part of the technical ecosystem that shaped how people understood engine-vs-human strength and style. The period was not built by one engine alone. It was a dense field of strong programs pushing each other upward, and Tanase Shogi was one of the meaningful contributors in that field.
In that sense, its historical value is less about one famous single game and more about continuity: a line connecting university-origin engine culture, commercial software packaging, and serious tournament competition.
Why It Mattered
- Developer continuity and reinvention: the engine is directly connected to the Tōdai Shogi line, but with a deliberate redesign by the same developer, 棚瀬寧.
- Verified high-level results: Japanese tournament records place Tanase Shogi among top WCSC finishers in its era.
- Historical bridge role: it links early academic-commercial software traditions to the stronger, more public computer-shogi period that culminated in Denōsen-scale attention.
For shogi fans looking back, Tanase Shogi is a reminder that progress in engine strength came from a competitive ecosystem. Some engines became famous through one dramatic match. Others, like Tanase Shogi, mattered because they consistently raised the level of the field.
Sources (Japanese)
- Wikipedia日本語版「東大将棋」(oldid=108185328): https://ja.wikipedia.org/w/index.php?title=%E6%9D%B1%E5%A4%A7%E5%B0%86%E6%A3%8B&oldid=108185328
- Wikipedia日本語版「世界コンピュータ将棋選手権」(oldid=106966325): https://ja.wikipedia.org/w/index.php?title=%E4%B8%96%E7%95%8C%E3%82%B3%E3%83%B3%E3%83%94%E3%83%A5%E3%83%BC%E3%82%BF%E5%B0%86%E6%A3%8B%E9%81%B8%E6%89%8B%E6%A8%A9&oldid=106966325
- Wikipedia日本語版「将棋電王戦」(oldid=105728484): https://ja.wikipedia.org/w/index.php?title=%E5%B0%86%E6%A3%8B%E9%9B%BB%E7%8E%8B%E6%88%A6&oldid=105728484
- Wikipedia日本語版「ツツカナ」(oldid=95922502): https://ja.wikipedia.org/w/index.php?title=%E3%83%84%E3%83%84%E3%82%AB%E3%83%8A&oldid=95922502
- 第24回世界コンピュータ将棋選手権 公式ページ: https://www.computer-shogi.org/wcsc24/