Some thoughts about no-komi Go

I was thinking a little today about komi, perfect play, and solving Go.

We can define a perfect move as a move that doesn’t lose any points (those points being the ones scored at the end of a perfect game following the move), and perfect play as a series of those perfect moves. So, if we imagine a no-komi opening where White is a perfect player and Black is not, we can divide Black’s potential moves into three classes:

  1. Perfect. Moves that don’t lose any points.
  2. Mediocre. Moves that lose points but still leave some first-move advantage.
  3. Drawing-Losing. Moves that lose all the first-move advantage.

Sometimes it is fairly clear what the perfect move is, for instance in a forced joseki line. During much of the opening it’s unclear which move is perfect and which is just mediocre – for instance, playing nirensei vs nirensei and deciding between invading 3-3, approaching a corner, splitting the side, or playing sanrensei.

I think a good measure of strength is how far into a no-komi opening the Black player can go without necessarily playing perfect moves, but without playing a losing move (again presuming that White plays perfectly.)

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I think another way to phrase your proposed measure is:

How many moves could one play as black in a no-komi game against a perfect player before squandering the first move advantage?

I’m not sure if that’s necessarily a good measure of strength. How long one lasts under this criteria may just depend on the timing of when complicated fighting breaks out, or how well one has memorized and understood some key joseki/fuseki.

If we are measuring strength with respect to perfect play, I think a more natural measure would be:

How much handicap (in terms of stones and/or reverse komi) would one need to beat a perfect player?

I think the answers to these two questions would be correlated, but not always directly proportional.