From: bogin yahoo co jp> Date: 14 sep 2007 Subject: RE: Error in Tsume No.2863??? --0-1633535787-1189766726=:59894 Content-Type: text/plain; charset=iso-2022-jp I don't think there is anything wrong with wither the problem or the solution. Thare are some important differences between the rules of tsume shogi and the rules of regular shogi. In addition to the regular rules of shogi, in tsume shogi the mating side has to 1. mate in the fewest number of moves possible 2. make every rule a check (thus there can be no waiting moves) 3. have no pieces in hand when at the end of the mating sequence. the defending side has to 1. make the best possible defensive moves (that is to say find the sequence of defensive moves the prolongs mate for the longest) 2. avoid any moves (interpositions or piece drops) that only unnecessary prolong the inevitable mate. That is to say, the defending side can't just drop pieces to delay a forced mate by a single move. Any defending move (including drops or interpositions) must serve a valid purpose. So, it that position, the only correct first move is 1. G5e+ Now the defending side must play 2. Rx5e because 2. Sx5e leads to 3. S5dx6e which is mate. The is called hayatsumi and is an invalid solution because (1) the defending side did not make the best defending move and (2) the mating side still has pieces in hand. So, after 1. G5e+ 2. Rx5e, the next correct move is 3. S6f-5g. You have to be specific about which silver you move. If you just say 3. S5g then your solution will be invalid because there are 2 silvers (6f and 4h) that can move to that square. Now, the defending side has three possible replies: (1) 4. Sx5g and (2) 4. Nx5g= and (3)4. Nx5g+. None of those replies can prevent the mate. If 4. Sx5g then 5. G4g+ mate. Both knight moves allow 5. G6f+ mate. Even though there are two different final mating moves in the final position this is still considered a valid solutiuon because the number of moves in the final solution is the same, all the mating player's pieces in hand have been used and the defensive player has made the best possible defensive moves in prolonging the mate. The other solutions mentioned may surely lead to mate but not by tsume shogi rules so therefore they are not considered valid. --------------------------------- Easy + Joy + Powerful = Yahoo! Bookmarks x Toolbar --^---------------------------------------------------------------- This email was sent to: shogi-l shogi net EASY UNSUBSCRIBE click here: http://topica.com/u/?a2i6Ys.aCGIy8.c2hvZ2kt Or send an email to: shogi-unsubscribe topica com For Topica's complete suite of email marketing solutions visit: http://www.topica.com/?p=TEXFOOTER --^---------------------------------------------------------------- --0-1633535787-1189766726=:59894 Content-Type: text/html; charset=iso-2022-jp
I don't think there is anything wrong with wither the problem or the solution. Thare are some important differences between the rules of tsume shogi and the rules of regular shogi.
 
In addition to the regular rules of shogi, in tsume shogi
 
the mating side has to
1. mate in the fewest number of moves possible
2. make every rule a check (thus there can be no waiting moves)
3. have no pieces in hand when at the end of the mating sequence.
 
the defending side has to
1. make the best possible defensive moves (that is to say find the sequence of defensive moves the prolongs mate for the longest)
2. avoid any moves (interpositions or piece drops) that only unnecessary prolong  
the inevitable mate. That is to say, the defending side can't just drop pieces to delay a forced mate by a single move. Any defending move (including drops or interpositions) must serve a valid purpose.
 
So, it that position, the only correct first move is
 
1. G5e+
 
Now the defending side must play 2. Rx5e because 2. Sx5e leads to 3. S5dx6e which is mate. The is called hayatsumi and is an invalid solution because (1) the defending side did not make the best defending move and (2) the mating side still has pieces in hand.
 
So, after 1. G5e+ 2. Rx5e, the next correct move is 3. S6f-5g. You have to be specific about which silver you move. If you just say 3. S5g then your solution will be invalid because there are 2 silvers (6f and 4h) that can move to that square.
 
Now, the defending side has three possible replies: (1) 4. Sx5g and (2) 4. Nx5g= and (3)4. Nx5g+. None of those replies can prevent the mate.
 
If 4. Sx5g then 5. G4g+ mate. Both knight moves allow 5. G6f+ mate.
 
Even though there are two different final mating moves in the final position this is still considered a valid solutiuon because the number of moves in the final solution is the same, all the mating player's pieces in hand have been used and the defensive player has made the best possible defensive moves in prolonging the mate.
 
The other solutions mentioned may surely lead to mate but not by tsume shogi rules so therefore they are not considered valid.
 

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