I tried whether it is possible to play to loose in Go;
and in order to shorten the experiment we used the smallest board possible. Game Finished (online-go.com)
What puzzled me is that it should have stopped me from placing a stone when white just took out my last one - but I could play right away again on that very same spot.
Shouldnโt the KO-rule prohibit this game turning into an endless game?
Youโre playing with Japanese rules, which only has the ko rule that a board position may not repeat the one from two moves ago. So, youโre not allowed to recapture a ko. But, longer cycles are allowed, such as triple koโs (usually this will end the game in a โno resultโ by some arbiter).
Prohibiting repetition of any previous board state is called โsuperkoโ, which comes in several flavours. The Chinese ruleset uses superko, so if you were to play your game under Chinese rules, then I expect it to be ending.