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Any educated guesses to the following question would be appreciated:
“Would making it illegal (instead of a draw) to repeat a position a third time be more advantageous to attackers or to defenders? Or would it affect both equally?”
(I am not advocating such a rule change, I am just philosophically curious.)
Thanks.
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You’d have to clarify the proposed rule a bit. What if creating the third occurrence is the only legal move? Would this now be illegal, so that the position would be a stalemate (or checkmate if the player is in check), or would there be an exception to the anti-repetition rule for the case where there is no other legal move?
Bill Smythe
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Hmm, I had not thought of that.
For the present purpose I am mostly assessing situations where both players do have other legal moves available.
To address your point – If a player’s only legal move creates a third repetition, then the game should be a stalemate; right?
Thanks.
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What if the player is in check? Then how is that different from the definition of checkmate?
Alex Relyea
In most perpetual check cases, it would be the player giving the check that would be forced to vary, which would reduce the frequency with which the stalemate/checkmate would occur. That is clearly a disadvantage to that player. It would effectively eliminate that technique from the defender’s repertoire when other legal choices are available.
Unless, of course, he is in check, in which case it would be checkmate.
This variation creates a whole slew of questions on its own. For example, it has always been the rule that two positions are considered identical only if all pieces are on the same squares AND all possible moves (for both players) are the same. This includes future moves, e.g. two positions are not identical if the right to castle has been lost in the meantime.
Now let’s look at our generic perpetual check under this proposed rule. White plays 1. Qd3-g6+, and (for one reason or another) black’s only legal move is 1…Kg8-h8. White then plays 2. Qg6-h6+, and black’s only legal reply is 2…Kh8-g8. The game continues 3. Qh6-g6+ Kg8-h8 4. Qg6-h6+ Kh8-g8, and now we have a situation where it is apparently illegal for white to create the third occurrence with 5. Qh6-g6+. But is it? It seems that black’s possible moves would not be the same. He would no longer be allowed to reply 5…Kg8-h8, since that would create a triple occurrence of its own. Therefore, it could be argued, the positions are not identical, and white should be allowed 5. Qh6-g6+, and in fact, black would then be checkmated, since his only otherwise legal reply would generate the third occurrence.
One could take this a step further, and argue that black should then be allowed 5…Kg8-h8, since that, too, creates a new position (white’s possible moves are not the same).
In fact, one could take this argument one step at a time, ad infinitum. Thus, the proposed rule seems self-contradictory, at least in this example.
Bill Smythe
More nonsence from the nonsence factory?!
Absolutely. But we’re sure having a lot of fun with it. 
I’m glad the original poster stated he was not seriously advocating this rule change. That fact gives the rest of us a little more poetic license.
Bill Smythe
Generically, without even knowing exactly what rule is planned, I would say the change would help the attacker.
Assuming of course that the attacker has the advantage. If the attacker is a rook down and forcing a perp to avoid losing, then removing that possibility would hurt him.
But otherwise, if we didn’t let the defender play the same defense a third time, it could break his position.
Depends how you define “attacker” and “defender”.
Is the person who has a lot of checks available the “attacker”, even if he is a rook down? If so, such a rule would hurt the attacker.
But I would be inclined to call that player the “defender”, whose line of defense consists of a perpetual check.
Bill Smythe
This rule does exist in XiangQi (Chinese Chess). It’s pretty complex, and I don’t really understand all the details. The fact that stalemate is a win in that game kind of eliminates one of the questions raised here, though.
–Fromper
Our discussion here, even though tongue-in-cheek, got pretty complicated. So I’m not surprised that a game which really tried to implement that rule would run into all sorts of complications.
Bill Smythe
Doesn’t Go have a rule of this sort?
Yup.
Ko (no repetition of the same shape)
Rule: If recapturing a stone would recreate the same board position from the previous move, the position is called ko, and the recapturing move is illegal.
That sounds quite a bit simpler.
It reminds me of a chess variant I tried once, in which pieces (except pawns and kings) are not moved, they are copied. For example, after 1.Ng1-f3, white still has his knight on g1 as well as a new one on f3.
At one point I had a knight on, say, f3, and my opponent had one on d7. I moved (oops, I mean copied) mine from f3 to e5. He then copied his from d7 to e5, capturing mine. I then recaptured (recopied) mine from f3 to e5, and after a few more moves like this, we ended up with a draw by repetition. I guess this is the sort of thing the Ko rule is designed to prevent in Go.
Bill Smythe