Assumptions of yose problems

    Keywords: EndGame, Problem

Often yose problems seem ill defined. The evaluation of a play, and sometimes the correct local play may depend on what stones are on areas of the board that are not shown.

On the other hand, showing the surrounding areas in detail seems artificial. As a rule the details are irrelevant. Also, especially with medium and large yose, the surrounding areas are not well defined when those plays are made in a real game.

I have identified a few assumptions that seem to be standard. For instance, one is that the threat to enter undefined opposing territory is sente. This assumption sometimes leads to plays being double sente, which we know is not true for evaluation, even though in practice a play may be double sente, depending on the other plays on the board. Those plays are only shown in full board yose problems, for which we require no assumptions.

Now I wonder if everything falls under one assumption:

All relevant stones are shown.

That does not mean that you can assume that the board is empty. In that case, you might want to play somewhere else. ;-) But that assumption works pretty well if you are addressing the question of how to play locally. It also does not adequately address ko evaluation, but the relevant assumptions for that need to be stated, anyway.

Hmmm. I think that we can make another assumption.

All points on which to play are shown.

What I mean by that is that correct play for both sides can be made on the points shown, for the yose under consideration. If it is sente, and the opponent ignores it, the threat may be to play on points not shown, but carrying out the threat is not correct play. It is not necessary to know the exact size of the sente threat to know that a play is sente. ;-) It is necessary to know details to evaluate a gote, however.

These are new musings, but I think they will work pretty well. :-)


Jan: Couldn't you just say "The temperature on the rest of the board is less than one", so that everything in the yose problem is important?

Bill: There are two problems with that. First, a play may be sente at one temperature, gote at another. The character of a play depends mainly on how it is played when the ambient temperature is approximately the same as its miai value.
Second, correct play may depend on the ambient temperature.

Assumptions of yose problems last edited by ArnoHollosi on September 15, 2005 - 11:00
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