johnlspouge: Saturday (Very Difficult): White to play and win.
Material: even. White has K-side pressure based on the g-file controlled by Rg1. The Bh4, Pe5, and Pf4 control dark squares near the Black Kh7; Bf3, Ne3, and Ng3, light squares. In particular, the 2Ns are focused on Pf5, and the capture gxf5 makes the Black Qf7 vulnerable to the move Bh5 from the battery, Qd1 and Bf3. White has maximal development: only Ra1 remains inactive, but can move to the K-side in a single move under the right conditions. In addition, the usual conditions for a K-side strike exist, namely, the Black Ba3, Nc7, and Nd7 are essentially out of defensive play on the Q-side, giving White the local superiority a sacrificial attack requires.
Candidates (23.): Ngxf5
increasing the scope of Rg1 and threatening 24.Nxg7 25.f5 or 24.Bg4.
23…gxf5 (or lose a P under unfavorable conditions) 24.Bh5
Black has 2 feasible responses.
(1) 24…Qg8 25.Bg6+ Kh8 26.Bxf5 (threatening 27.Bxd7)
Black can sacrifice an exchange with 26…Rad1, 26…Rfd1, or 26…Rxf5, leaving White with R+2Ps vs. B+N and a winning attack fueled by 2 central passers. There are 2 other feasible responses, a dismal retreat 26…Nb8, bottling the Q-side up even more tightly than at present, and 26…Rf7.
(1.1) 26…Nb8 27.Bf6 Rf7 28.Qh5,
threatening 29.Rxg7 Rxg7 30.Qxh6+ and possibly 31.Qh7#.
There is no adequate defense.
(1.2) 26…Rf7 27.Bxd7 Rxd7 28.f5,
threatening 29.f6 30.Qg4.
There is no defense leaving Black less than a P down.
(2) 24…Qe6 25.Bg6+ (threatening 26.Qh5 27.Bg5 28.Bxh6)
25…Qxg6 26.Rxg6 Kxg6 27.Qf3,
threatening 28.Rg1+ 29.Qh5 then 30.Qg6 or 30.Nxf6.
There is no way to defend both Pf5 and Bg7, and once one of them falls, the White pieces pour in.
Time to peek. (No crash and burn <today>.) Time to check the kibitzing. I should fail so handsomely as you, <dzechiel>: initially, I also quailed at throwing more pieces onto the fire with my line (2) 25...Qxg6. The Bh4 made a good anchor for the attack, however, so positionally, it was nearly certain the Q would find a stray piece in Black's Q-side tangle. The calculations <were> reassuring, however.
I was most concerned about refusal of the sacrifice, because Pf4 was loose. I will fire up my 512K Mac and see what it says :)