Forced Takeback Go
In this variant, similar to Choice Go, you have the option of forcing your opponent to take back most recent move and replace it with another, but only once per turn. If you use this option, you opponent chooses another move to play, and you must stick with it. After two successive passes, the game becomes regular go, so that the last point can be taken.
For example, if you have a large group in atari, you can ignore it. When your opponent tries to capture it on his turn, you force him to make a different move. You must allow the second move he makes, even if, after seeing it, you'd rather have him play the first! :-)
This game can get complicated fast. Try it out, and let me know what you think!
No Go is a good teaching game for ko-fighting. Players keep on denying eachother the same big point until an even bigger move turns up. The biggest point in the game will remain on the board undecided, like the eye of a tornado.
It's nice to have a variant where a group of stones in atari can survive - and even earn 1 point!
No Go was previously mentioned by Andre Engels http://www.win.tue.nl/~engels/go/variants.html
No Go is comparable to Neurotic Go. In Neurotic Go however a player has to decide which countermove he fears most before his opponent has put.
Note: the name "NoGo" has been more recently used to refer to no-capture go, or AntiAtariGo. It was studied under this name at the 2011 BIRS Combinatorial Game Theory workshop, where a human tournament and a computer tournament were held. -- BobHearn
JoeSeki: I tried take-back go tonight at the club, and found some very interesting quirks about the game. Like a ko without the proper amount of stones as below the marked white stone starts a ko even though white is one stone short
ChessWhiz: Yes, that is quite strange. As you play more, you may find some other interesting quirks! For example, a large ko on the board can slow down the game, and gives a weird advantage to the player who takes first in the ko.
Malcolm: Personally, I prefer to remove the clause "After two successive passes, the game becomes regular go, so that the last point can be taken". I would rather say: "after two successive passes, the game is over and can be counted!". It's nice to have a variant where a group of stones in atari can survive - and even earn 1 point!
I played this game once in the 90s in France at a Go Variants event where it went under the name "go pyschologique".
A natural variant of Forced Takeback Go is to limit the total possible number of refusals a player can make during a game. This is called "Veto Go" in the page King's Order. Actually I think Veto Go is a better name than "Forced takeback Go" for the variant described in this page...
This is one of my favourite Go variants.
A further variant is to let just one player refuse moves, and give the other some compensation via a komi. Superpower Go develops this idea.
Tony: This game is elsewhere described as "No Go" which seems a very nice name! It is a good teaching game for ko-fighting. The biggest point in the game will remain on the board undecided, just like Malcolm says, like the eye of a tornado.