Puzzle of the week #105

Level:
5-Queen
Chess Diagram:

We saw last week how precise we need to be in pawn endgames. They are the backbone of chess knowledge, the last chance to win a game or save half a point, influencing the play in any game long enough to reach the endgame. A player capable of understanding and mastering them will make a definite jump ahead toward becoming a master. Over the years we learned and applied a few solid principles when facing such endgames. They are invaluable and should be used at all times while preparing your plans and executing them. Let's practice them again in this apparently straight forward study. Your tasks:
a) Analyse the position and propose a plan for both sides (10 points)
b) White to move and draw (10 points)

Total available points for this puzzle is 20. The answers will be published next week together with puzzle #106.

Puzzle #104 solution:
This was the end of the game between Aseev - de Vreugt, 2001. Thanks a lot for your intuitive moves! In such unusual endgames, the first thing you need to look at is what would happen if you could simplify it to a Kings and pawns endgame. Based on this your intuitive move should be 1.Rxg5! ... It is good to see that even if some of you first intended to move something else, you ended up analysing the exchange sacrifice anyway.
Since there are no passed pawns, White should look for the possibility to create one. The only chance to do so comes along the "d-" file where Black has a backwards pawn. Once you reach this point, the rest is pure calculation:
1.Rxg5 Kxg5 2.e5 exd5
If 2... dxe5 3.d6 Kf6 4.g5+! ... 1-0 The Black King is blocked by its own pawns
3.exd6 Kf6 4.Kd4 Ke6 5.Kc5 d4 6.Kc6 d3 7.d7 Ke7 8.Kc7 ... 1-0 White transforms first because its pawn was more advanced.
Or 5... Kd7 6.Kxd5 ... 1-0 and this is an easily won endgame. Example of how the game could end: 6... f6 7.Kc5 Kd8 8.Kc6 Kc8 9.d7+ Kd8 10.Kd6 f5 11.g5 ... and mate in 4.
A correct and precise answer contains all the above, or in other words you need to analyse all the above before you can decide if you should go for the exchange sacrifice or not.

Correct solutions:
Andy Q - 15 points
Andy Y, Alex, Nathaniel, Jeffrey - 14 points
Amir - 12 points
Edwin - 10 points
Owen, Humphrey, Karl - 8 points
James - 5 points

James - 10 points for puzzle #103
Nathaniel - 5 points for puzzle #103

STANDINGS

Andy Y, Andy Q - 94 points
Owen, Karl - 88 points
Amir - 84 points
Alex - 80 points
Humphrey - 73 points
Edwin - 68 points
Jeffrey - 61 points
James - 46 points
Nathaniel - 19 points
Rick, Marko - 10 points

Comment:

Chess geometry