Longest Honinbo Title Game (version 1)
The longest game by number of moves, and perhaps also by time, ever played in a Honinbo title match took place over two days around 10-12 March 2022, between Iyama Yuta and Ichiriki Ryo, as the first game of the 77th edition.
Iyama had been the dominant Japanese professional for about a decade, and had held all seven major domestic titles in 2016 and 2017. Ichiriki, eight years younger, had begun to achieve success a couple of years before, winning the 2020 Tengen and Gosei. Most notably, he'd scored a landmark victory by taking the 2022 Kisei, a title which Iyama had held since 2013.
The Go world had become very interested in the progress of the Honinbo match, as it was being said that if Ichiriki took this title a "new era" would be ushered in, in which Iyama would no longer be viewed as the clear Japanese #1.
After losing the Kisei, the Honinbo had become the only title that Iyama had held continuously since before 2020, and indeed he'd kept it since 2012, having taken the honorary name Monnyu. Another reason for the great attention on the match was that if Iyama could win one more edition, he'd be able to beat the record of ten consecutive times set by Cho Chikun in 1998 (though Cho won twelve times overall).
The game lasted for 357 moves. The decisive margin was half a point.
This was 87% of the length of the longest professional game from 1950 to 2022, Hoshino Toshi--Yamabe Toshiro, 411 moves. It was 83% of the length of the currently longest professional game, Yang Zixuan--Zhang Kaixin, 431 moves.
- Commentary in the Mainichi Shinbun, by So Yokoku, possibly with input from Ogata Masaki
- Pandanet UGI version of the commentary