Puzzle of the week #318

Submitted by Eugen on Wed, 05/17/2017 - 10:45
Underpromotion
Level
5-Queen
Chess Diagram
[Event "Puzzle #318"][Date "2017.05.17"][Result "1-0"][SetUp "1"][FEN "2k5/8/2K1P3/b7/8/6B1/8/8 w - - 0 1"]
White has a minimal advantage and that still looks sufficient for a win. Black does not seem to be able to stop the extra pawn from promoting. Your tasks:
a) What last trick can black try to save the game?
b) Find the correct 2 different lines white can choose from to win

Total available points for this puzzle is 25. The answers will be published next time together with puzzle #319.

Puzzle #317 solution:
Game Simaghin – Zagorianski, Ivanovo 1944. The most complete answers were by Jalen:
a) Although white can equalise the material, BLack's pieces aren't in position yet, and the black king is stuck in the center, so white should exploit this and try to find a combination to win
c) The king is overloaded because it is forced to defend Rf7, plus Rc8 and Ne7 if White attacks the back rank

[Event "Puzzle #317"][Date "2017.05.02"][Result "1-0"][SetUp "1"][FEN "2r1k3/p3nrR1/1p1p4/2p1p1p1/2P1B3/2PP1P2/P5K1/7R w - - 0 1"]1. Rh8+ (1. Bg6 Nxg6 2. Rxg6 Kd7? 3. Rhh6 {Deryk}) 1... Kd7 (1... Rf8 2. Rh6 (2. Rhh7 Rc7 {Yakov}) 2... Rd8 (2... Rf7 3. Rxf7 Kxf7 4. Rxd6 {Bradley}) 3. Bc6+ Nxc6 4. Re6+ Ne7 5. Rexe7# {Cody}) (1... Ng8?? 2. Rhxg8+ Ke7 3. Rxf7+ Kxf7 4. Rxc8 {Benjamin}) 2. Bc6+ Ke6 (2... Rxc6 3. Rxf7) (2... Nxc6 3. Rxf7+) (2... Kxc6 3. Rxc8+ Nxc8 4. Rxf7) 3. Rh6+ Rf6 4. Bd7+ Kxd7 5. Rxf6 {Jalen}

Correct solutions:
Jalen - 25 points
Coco, Cody - 17 points
Deryk, Benjamin, Yakov - 5 points

Bradley - 8 points for #316

Standings:
Jalen - 215 points
Coco - 196 points
Cody - 194 points