Most simultaneous games of Go

According to Official Guinness Records,

The record for the most games of Go played simultaneously is 500, involving 1,000 players and it was set at Take-machi-dohri and Chuo-cho Shopping Streets, Oita, Japan on 6 June 1999.

For a complete list of 1999 records, please visit 1999 Guinness Records in Japan.

Other Japan records that might interest you:

• Longest bridge, cable suspension bridge
• Youngest golfer to score their age
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• First Pacific crossing by hot air balloon
• Most pages in a periodical magazine