Puzzle of the week #361

Chess Diagram: 

[Event "Puzzle #361"][Date "2019.01.27"][Result "1-0"][SetUp "1"][FEN "6k1/5p1p/p4p2/2r5/2br4/5B2/P4PPP/2R1R1K1 w - - 0 1"]

Play in this game has reached the endgame and material is equal. It is white to move. Your tasks:
a) Analyse the position and decide if anyone is better; please explain why
b) Find the best play for white

Total available points for this puzzle is 20. The answers will be published next time together with puzzle #362.

Puzzle #360 solution:
Game Reshevsky – Ivanovic, Skopje 1976. This week's best answers are by the top scorers:
a) Black has many advantages in this position including:
- he has a long a7-bishop pointing toward the king
- his bishop, queen, knight and rook are in the attack
- whites king is in the corner with almost no pieces to defend him
b) The shortest way to win is mate in 4

[Event "Puzzle #360"][Date "2019.01.13"][Result "0-1"][SetUp "1"][FEN "4r3/b4pk1/p3p3/Pp1pPnpp/1Pr4q/2P2B2/3BRPPP/2R1Q2K b - - 1 27"]27... Qxh2+ 28. Kxh2 Rh4+ 29. Kg1 Ng3 {Rh4-h1# follows no matter what white does}

The answers to the riddle were:
Question: what is it that a Queen cannot do that every other piece can?
The Queen can't capture a more valuable piece (Kings can't be captured) than itself while all other pieces can.
The Queen cannot deliver discovered check.

Correct solutions:
Coby, Matthew - 20 points
Aiden - 17 points
Zhengyu - 11 points
Blake - 10 points
Glyn - 9 points
Walter, Brian, Joey, Mengbai - 5 points
Lucas - 2 points

Chess riddle:
Zhengyu, Mengbai, Blake - 5 points
Aiden, Brian, Lucas, Matthew - 1 point

Matthew - 21 points
Coby - 20 points
Aiden - 18 points
Zhengyu - 16 points
Blake - 15 points
Mengbai - 10 points
Glyn - 9 points
Brian - 6 points
Walter, Joey - 5 points
Lucas - 3 points


Relative pin