If black king was in check, the only escape square is c4 just now. If white rook could deliver a check from forth rank, then game is all but over. However, black’s white-squared bishop is protecting a4 and white’s knight on b4 is blocking its rook’s path. So, eliminate the bishop and clear way for rook by
1.Nxc6+ Rxc6 2.Ra4+ Rb4 3.Rxb4+ Rc4 4.c3#
At the first move, black need not capture white’s knight and has the following alternate move – 1…Kc4 2.Ra4+ Kb5 (2…Rb4 3.Rxb4#) 3.Nd4+ Kxa4 4.Ra1#
Black King is in a mating net! If only c4 was covered c3 or e3 would be mate! 1.Nxc6+!! Forces mate in 4 even though white is 2 pieces behind! >A-1…..Rbxc6.2.Ra4+.Rc4.3.c/e3#! >B-1….Rcxc6.2.Ra4+.Rb4.3.Rxb4+.Rc4.4.c/e3#! >C-1….Kc4.2.Ra4+! >>C1-2…Kb5.3.Nd4+!.Kxa4.4.Ra1#! >>C2-2…Rb4.3.Rxb4#!! Beautiful!
Took me a while to solve this, since two quiet moves must be found: 1. e3+ Kc4 2. Nd3!! Threatens – 3.Rc5+ Nxc5 4. Ne5# as well as – 3.Ne5+ Nxe5 4.Rc5# To escape, Black must try to make square b4 accessible to the king. 2. … Rxa6 2. … Bb5 (blocks the rook’s way to c5) 3. Rb1 Be7 (threat Rb4#) 4. Rb4+ Bxb4 5. Nb2# 3. Rb1!! … and the trap is closed. 3. … Be7 3. … Rxa5 4. Rb4# 3. … Rb6 4. Rc5+ Nxc5 5. Ne5# Now 4.Rb4 is no more mate, but… 4. Rb4+! Bxb4 5. Nb2# Beautiful!
1.Nxc6 (it is important to control the only escaping square of the king which can only be attacked by a (white) rook. the c6 knight is untouchable because of 2.Ra4 and mate. Because of this 1…Rc4 is forced. Then, 2.Ra4+. if 2…Rc4, 3.c3+ is a checkmate. 2…Kb5 is still a forced move. 3.Nd4+(or Nxa7+). 3…Kxa4 is forced and 4.Ra1+ is checkmate. Have a nice day☺
Took me quite a while to get this one. I eventually figured it out in my efforts to find a way to close the c4 square from black’s king- clear the b4 knight out of the way so that rook can come to a4, with check if necessary, and I stumbled into the method of blocking the square with black’s own rook:
1. Nc6!
I looked for a long time other first moves, especially the two pawn checks and Rb1, and I am now pretty certain they all lose for white. Continuing:
1. ……Kc4 (trickiest defense!) 2. Ra4
This leads to mate, but Rha1 also looks winning to my eye, though I haven’t done more than a cursory eyeball glance. Continuing:
In all my years of playing chess, reading and playing through games, and studying chess problems have I never seen this sort of mating arrangement. I have seen edge mates with rooks and queens where two side by side knights control the four squares locking the king on the edge, but never the same thing (three squares in this case) with one of the knights on the mating file/rank. Very pretty!
At move 1, black can’t prevent the mate, though those are less charming to me:
1. Nc6 Rbc6 2. Ra4 Rc4 (only legal move) 3. c3#
Of course, black can take at move 1 with the other rook allowing one extra move for the same basic mate.
N d3?
Nxc6+
If black king was in check, the only escape square is c4 just now. If white rook could deliver a check from forth rank, then game is all but over. However, black’s white-squared bishop is protecting a4 and white’s knight on b4 is blocking its rook’s path. So, eliminate the bishop and clear way for rook by
1.Nxc6+ Rxc6
2.Ra4+ Rb4
3.Rxb4+ Rc4
4.c3#
At the first move, black need not capture white’s knight and has the following alternate move –
1…Kc4
2.Ra4+ Kb5 (2…Rb4 3.Rxb4#)
3.Nd4+ Kxa4
4.Ra1#
Black King is in a mating net! If only c4 was covered c3 or e3 would be mate!
1.Nxc6+!! Forces mate in 4 even though white is 2 pieces behind!
>A-1…..Rbxc6.2.Ra4+.Rc4.3.c/e3#!
>B-1….Rcxc6.2.Ra4+.Rb4.3.Rxb4+.Rc4.4.c/e3#!
>C-1….Kc4.2.Ra4+!
>>C1-2…Kb5.3.Nd4+!.Kxa4.4.Ra1#!
>>C2-2…Rb4.3.Rxb4#!!
Beautiful!
Seems like c4 forces black to sacrifice the exchange to avoid mate, but I don’t see any forced mate.
Pawn e3
Took me a while to solve this, since two quiet moves must be found:
1. e3+ Kc4
2. Nd3!!
Threatens
– 3.Rc5+ Nxc5 4. Ne5#
as well as
– 3.Ne5+ Nxe5 4.Rc5#
To escape, Black must try to make square b4 accessible to the king.
2. … Rxa6
2. … Bb5 (blocks the rook’s way to c5)
3. Rb1 Be7 (threat Rb4#)
4. Rb4+ Bxb4
5. Nb2#
3. Rb1!! … and the trap is closed.
3. … Be7
3. … Rxa5 4. Rb4#
3. … Rb6 4. Rc5+ Nxc5 5. Ne5#
Now 4.Rb4 is no more mate, but…
4. Rb4+! Bxb4
5. Nb2#
Beautiful!
1.Nxc6 (it is important to control the only escaping square of the king which can only be attacked by a (white) rook. the c6 knight is untouchable because of 2.Ra4 and mate. Because of this 1…Rc4 is forced. Then, 2.Ra4+. if 2…Rc4, 3.c3+ is a checkmate. 2…Kb5 is still a forced move. 3.Nd4+(or Nxa7+). 3…Kxa4 is forced and 4.Ra1+ is checkmate. Have a nice day☺
1.c4 looks deadly for my instinct, and it proves so with a few seconds of variation analysis
Cheeky problem!.
1.Nxc6+ Kc4
(N at c6 is untouchable. 1….R(any)xc6 2.Ra4+ Rc4 3.c3#)
2.Ra4+ Kb5
3.Nd4+ Kxa4
4.Ra1#
Took me quite a while to get this one. I eventually figured it out in my efforts to find a way to close the c4 square from black’s king- clear the b4 knight out of the way so that rook can come to a4, with check if necessary, and I stumbled into the method of blocking the square with black’s own rook:
1. Nc6!
I looked for a long time other first moves, especially the two pawn checks and Rb1, and I am now pretty certain they all lose for white. Continuing:
1. ……Kc4 (trickiest defense!)
2. Ra4
This leads to mate, but Rha1 also looks winning to my eye, though I haven’t done more than a cursory eyeball glance. Continuing:
2. ……Kb5 (Rb4 3.Rb4#)
3. Nd4 Ka4 (only legal move)
4. Ra1#
In all my years of playing chess, reading and playing through games, and studying chess problems have I never seen this sort of mating arrangement. I have seen edge mates with rooks and queens where two side by side knights control the four squares locking the king on the edge, but never the same thing (three squares in this case) with one of the knights on the mating file/rank. Very pretty!
At move 1, black can’t prevent the mate, though those are less charming to me:
1. Nc6 Rbc6
2. Ra4 Rc4 (only legal move)
3. c3#
Of course, black can take at move 1 with the other rook allowing one extra move for the same basic mate.
1.Nxc6+ Kc4 2.Ra4+ 3.Kb5 Nd4+ Kxa4 4.Ra1#
1.e3 Kc4 2.Rc5#