= pass

John Tromp pointed out the peculiar consequences of superko rule if White does not connect in the lower left.

 

Black plays as the superko threat.

 

= pass

 

With normal superko rules, White 11 is prohibited as it repeats the outcome of White 7. All white stones are dead as the result.

Under Kee Rules, White 11 is not prohibited because the pass White 9 has lifted the positional superko.

 

= pass

Instead, Black 14, or any other stone play, is prohibited. Black can only make a pass play on this initialized board position (initialized by White 13), as he encountered the same initialized board position (initialized by White 9) previously.

The game ends by treating the board position as seki.

B. Sending-2-returning-1 + Seki with one-sided irremovable ko threat

 

Unlike John Tromp's sending-2-returning-1, White cannot even connect to remove the superko threat.

 

Black plays as the superko threat, which is a one-sided irremovable ko threat only available to Black.

 

= pass

 

With normal superko rules, White 8 () is prohibited as it repeats the outcome of White 4. All white stones are dead as the result.

Under Kee Rules, White 8 () is not prohibited because the pass White 6 has lifted the positional superko.

 

= pass

Instead, Black 11, or any other stone play, is prohibited. Black can only make a pass play on this initialized board position (initialized by White 10), as he encountered the same initialized board position (initialized by White 6) previously.

C. Unfilled simple ko on fully occupied board

 

White has two eyes but Black has only one. Can White capture all the black stones as we expect?

 

Black captures the ko by .

With normal ko rules, White's recapture is prohibited and the game will end there. It is not fair to White as Black does not resolve the ko when White is prohibited to make a stone play due to the ko.

Under Kee Rules, White can choose to pass first. Then after Black has responded by another pass (as he cannot do anything else), White can recapture (with the positional superko lifted by the passes) and then capture all the black stones as a fair outcome.

D. Triple ko without eyes

 

With normal superko rules, Black would capture all the white stones. It is the same under Kee Rules.

E. Triple ko with White having one eye but Black having none

 

With normal superko rules, Black would end up capturing two out of three ko's.

Under Kee Rules, White would be able to capture all black stones eventually because the positional superko can be lifted by a pass. This is a fair outcome because White has one eye but Black does not.

F. Triple ko with both players having one eye

 

With normal superko rules, Black would end up capturing two out of three ko's. It is the same under Kee Rules.

G. Bill Spight's 4×3 board

See SpightRules/Example.

 

This is a position similar to a ten thousand year ko. White takes the ko, but after Black passes White should not fill. Similarly, if Black can take the ko, then even after White passes Black should not fill.

With normal ko rules, Black's recapture is prohibited and the game will end there.

Under Kee Rules, Black can recapture after a pass by Black and then White. Then White can recapture too after a pass by White and then Black. The game would end with White's recapture because it is already the second time such board position is initialized. It ends up having the same outcome as normal ko rules.

H. 2×1 board

 

Starting from an empty board, can Black do better than a draw?

 

With normal ko rules, Black's recapture is prohibited and the game will end with White winning by 2 points. This means should be a pass and the game is a draw.

Under Kee Rules, Black can recapture after a pass by Black and then White. Then White can recapture too after a pass by White and then Black. The game would end with White's recapture because it is already the second time such board position is initialized, with White winning by 2 points. This means should be a pass and the game is a draw.

I. 2×2 board

 

Starting from an empty board, can Black do better than a draw?

With normal superko rules, Black would win by 1 point.

Under Kee Rules, the game is a draw.

J. 3×2 board

 

Starting from an empty board, can Black do better than a draw?

With normal superko rules, the game is a draw. It is the same under Kee Rules.