GameKnot: GameKnot related, Tactical Exercise #33698

GameKnot related: Tactical Exercise #33698

From	Message
johnjarvinen 23-Dec-10, 05:56	Tactical Exercise #33698 So apparently I failed this exercise because I didn't find the strongest way to mate even though it takes the same number of moves? Why does it matter? Isn't a mate in 4 with a queen sacrifice just as strong as mate in 4 without one? Can someone please explain why or maybe tell me who i can contact about it.
black_cat_hamlet 23-Dec-10, 14:45	Without checking it (I dunno how to get to it without the link) it's probably that your line isn't with a check, whereas the queen sac is with a sac, so the computer would prolong mate by checking your king...
johnjarvinen 23-Dec-10, 15:49	All moves in my line are forced with checks, where as the computer line isn't forced and includes one of these spite checks.
ganstaman 23-Dec-10, 17:25	What moves are you thinking about? 1...Qxh2+ isn't a mate in 4. tactics #33698
kingdawar 23-Dec-10, 17:38	I guess we need to know white's first move to judge
johnjarvinen 23-Dec-10, 23:58	White first move is Bf2 The continuation I found is 1... Nge3+ 2. Kg1 Qxh2+ 3. Kxh2 Rh8+ 4. Kg1 Rh1#
kingdawar 24-Dec-10, 00:22	Aren't you missing 4. Bh4? And isn't this line covered in the alternatives?
kingdawar 24-Dec-10, 00:25	OK it's quite possible this line isn't covered in the alternatives... because it's not the second-best line.
baronderkilt 24-Dec-10, 14:02	Like ganstaman said ... and to get the mate count you must remember to make all possible interference from the defender, even pointless checks and stupid moves to interpose vs check. (eg WT Bishop can interpose to h-file if Rh8+ there) Interesting problem. Even a third mate-like line there to make another red herring. Had to play thru several decent looking ideas. & a number of motifs to see which to apply. Fun. Believe they were: Line opening, Wt SQ weakness, Discovered Checks, Restriction of Defender, where three actually apply and one does not. I suppose you could throw in more like long diagonal control etc. if someone really wanted to list them out (which is a good idea imo, to "see what you can see" if someone is doing tactics study,..) , but i think further breakdown probably proves redundant to the themes employed.
johnjarvinen 24-Dec-10, 14:32	Yeah the bishop block... must've missed it. I've decided to switch to classic problems only because I hate finding a very nice looking line only to have the computer tell me its wrong.

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