The Nihon Saikyo League (日本最強決定戦, lit. Tournament to Determine Japan's Strongest Player) was a tournament league from 1956-1961. It was popularly called the "Six Strongest Tournament" or "六強戦," and was the precursor to the Meijin tournament. Each player played each other twice alternating colors, with no komi, and a time limit of 10-hours each with a 5-minute byoyomi.
- Season 1: 1956-1958 Go Seigen (8-0-2)
- Season 2: 1958-1959 Sakata Eio (8-1-1)
- This title was replaced in 1962 by the Meijin title.
- With the exception of Takagawa Kaku & Iwata Tatsuaki, all were 9-dan (at a time when there were very few 9-dans).
- Additional coverage at: http://gobase.org/games/japan/TITLES/saikyo.html.