# Optimal play and Komi

Optimal play is play where both players play the best move available all the time.

Also some (like Willemien) have the idea that optimal play should lead to a jigo score. And that the komi should be so that this becomes true. (so the relation is reversed not komi defines optimal play but optimal play defines the komi)

In normal Go on a 19x19 Goban the problem is that it is unknown what optimal play is and it will probably stay that way in the near future. Therefore komi cannot be defined in this way. (the whole game needs to be played optimal and we just cannot prove that a first move at the 3-4 point is better/equal/worse than a move at the 3-5 point)

On smaller boards like 7x7 it can be provisionally done. (see 7x7 best play) and therefore it can be (provisionally) proved the komi for 7x7 should be 9.

In most rulesets the Komi is not a natural number but something with a fraction just so that the result never can be jigo. Is this the right theoretical perspective?

### Discussions Welcome

Willemien's motivation against a fractional komi is the following: If you lose when you play your optimal you will lose. you will lose anyway. So what is good about optimal play?

Herman: Yes, I agree. The good thing about fractional komi is that it does not allow jigo. The bad thing about fractional komi is that it does not allow jigo, even when both players play perfectly :-)

Jay?: Possibly this is not yet an issue.

Slarty: The "best move" was not defined. Presumably it means a move that maximizes the final score difference (B-W for black, W-B for white) provided that the opponent responds with a best move.

Then if you lose despite optimal play, you have at least achieved the smallest loss, even though on that day komi would be obviously broken. One thing to be said for fractional komi, before that day: it pushes players to play for the win and perhaps deviate from optimal play in interesting ways.