Puzzle of the week #321

Level: 
5-Queen
Chess Diagram: 

[Event "Puzzle #321"][Date "2017.06.13"][Result "1/2-1/2"][SetUp "1"][FEN "8/8/8/6p1/5pP1/p4PpK/1p4PB/kB6 w - - 0 1"]

White's material advantage is deceiving; luckily it has to move first. Your tasks:
a) Analyse the position and explain what each side is trying to do
b) Play the best line (all possible variations) as white to reach your goal

Total available points for this puzzle is 20. The answers will be published next time together with puzzle #322.

Puzzle #320 solution:
Game Alekhine - NN, Groningen 1933. The best answer is by Coco:
"a) The main factor both sides have to consider for this endgame is the a-file passed pawn, the big question being whether black can catch it on time (either with the king or rook). If white manages to promote, white has a greater chance of winning, but if black stops it and captures it, white can be in trouble due to him being down a pawn. (very important in the endgame) By counting the squares white's pawn has to advance, we see that black's king is within the imaginary box and can catch the pawn on time, but luckily white's rook prevents the king from doing that. However, if black chooses to stop the pawn with the rook by doing Rh5-h8, white cannot prevent the white pawn from being captured, or can he?
b) Since black can only stop the pawn with the rook and not the king, we can limit black's counter play by moving the simple g4. This prevents black from going to h5 followed by h8 right away. The only thing black can do here is to try attack then capture the pawn with the rook"

[Event "Puzzle #320"][Date "2017.05.29"][Result "1-0"][SetUp "1"][FEN "8/4kp2/4p1p1/2p1r3/PpP5/3R4/1P1K1PP1/8 w - - 0 1"]1. g4 Re4 (1... b3 2. a5 Rd5?? 3. Rxd5 exd5 4. a6 {Benjamin}) (1... Rg5 2. a5 Rxg4 3. a6 Rh4 4. Rd8 Kxd8 5. a7 {Cody}) 2. a5 Rxg4 (2... Rxc4 3. b3 Rxg4 4. a6 Rh4 5. Rd8 {Coco}) 3. a6 Rg1 (3... Rh4 4. Rd8 Kxd8 5. a7 {Coco}) 4. a7 Ra1 5. Ra3 bxa3 6. a8=Q a2 7. Ke2 {Game line, black resigned here}

Correct solutions:
Coco, Cody - 12 points
Benjamin - 6 points
Yakov - 2 points

Deryk - 7 points for #318

Standings:
Jalen - 260 points
Coco - 239 points
Cody - 237 points
Bradley - 224 points
Benjamin - 136 point
Deryk - 118 points
Uros - 63 points
Dheera - 45 points
Yakov - 41 points

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