A double ko and two separate kos can also form a quadruple ko.
A quadruple ko may lead to a game ending in no result if neither player is willing to back down from the ko fight, though some modern rulesets handle it with the superko rule. It is reported that a total of eight quadruple kos have occurred in professional Japanese play. Eleven examples are given on Quadruple Ko.
- In the 2005 Southern Great Wall Cup, a quadruple ko occurred in the match of Chang Hao versus Lee Changho and the game ended in no result. SGF
- In the preliminaries for the 25th Kisei, the game on April 6th 2000 between Doi Makoto and Hasegawa Sunao ended in no result due to a quadruple ko that occurred relatively early in the game. The game was replayed, with Hasegawa winning. SGF.
- An amateur game from the 2003 Frankfurt Go Tournament (Simon Kober 16 kyu versus Bjoern Wenzlaff 18 kyu) also included a quadruple ko. A photo is on the cover of DGoZ 3/2003.