[Event "Endgames: References"]
[Site "https://lichess.org/study/vMmllPNw/AAQ1gVdn"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
[Annotator "https://lichess.org/@/jomega"]
[ECO "?"]
[FEN "6q1/7k/1r2NQ2/1p4p1/5PP1/1K3p2/8/8 w - - 0 1"]
[Opening "?"]
[SetUp "1"]
[UTCDate "2018.12.07"]
[UTCTime "17:15:29"]
[Variant "Standard"]

{ The following are some of the references I used in the endgame studies.

- Silman's Complete Endgame Course: From Beginner to Master, Jeremy Silman [SCEC]
- The Complete Book of Chess Strategy, Jeremy Silman [CBCS]
- Practical Chess Endings, Irving Chernev [PCE]
- Basic Chess Endings, Reuben Fine [BCE]
- A Guide to Chess Endings, Dr. Max Euwe and David Hooper [GCE]
- Tarrasch: The Game of Chess, Dr. Siegbert Tarrasch [GOC]
- My System, Aron Nimzovich [MS]
- Wikipedia

[Troitzky 1929]
The given position is interesting. White is down the exchange and a pawn. Black has two passed pawns. Black is threatening to play ...Qxe6+ forcing an exchange of Queens and winning. Indeed, Black has the Knight pinned to White's Queen and King!

However, White has an attack on the King using his Queen, Knight, and pawns. Perhaps White can get a mate or a Knight fork? Also Black's Rook is not defended so perhaps there is a double attack that would win it. But what to do about the pinned Knight and the passed Black f-pawn?
- } 1. Qf5+ $1 { Perhaps White finds two candidate moves by looking at all his checks. He sees that 1.Qe7+ leads to at least a draw, while 1.Qf5+ might lead to the win of the Queen or mate. } ( 1. Qe7+ Kg6 2. f5+ Kh6 3. Qf6+ Kh7 4. Qe7+ Kh8 5. Qf6+ $10 { White makes no progress this way. } ) 1... Kh8 ( 1... Qg6 $4 { This move does not work and it does not matter where on the b1-h7 diagonal the White Queen is. } 2. Nf8+ $18 { The Knight fork wins the Queen. } ) ( 1... Kh6 $4 { This move does not work and it does not matter where on the b1-h7 diagonal the White Queen is. } 2. fxg5+ Qxg5 { Forced. } 3. Qxg5+ Kh7 4. Qg7# ) 2. Qe5+ { White saw that 2.Qf6 could lead to a draw by repetition, while this move keeps the draw in hand. } 2... Kh7 ( 2... Qg7 $4 { This fails throughout because White has two attackers on g7 after a check anywhere on the diagonal a1-h8. } 3. Qxg7# ) 3. Qe4+ { White had a fork of the King and Rook by 3.Qc7+, however after 3...Kh6 4.Qxb6, White wants to keep his Queen protecting his Knight so 4...f2, threatening to queen, wins the pinned Knight for Black. So White continues with the checks on the long diagonals. } 3... Kh8 ( 3... Qg6 $4 4. Nf8+ { Winning the Queen. } ) ( 3... Kh6 $4 4. fxg5+ Qxg5 5. Nxg5 f2 6. Qf5 f1=Q 7. Qxf1 Kxg5 8. Qf5+ Kh6 9. g5+ $18 { White wins. } ) 4. Qd4+ Kh7 ( 4... Qg7 $4 5. Qxg7# ) 5. Qd3+ $1 { White finds taking the Rook unclear. So he follows Silman's advice [SCEC] and plays "cat and mouse" with Black. } ( 5. Qxb6 gxf4 $1 6. Qc7+ Kg6 $1 7. Qe5 Kf7 $1 8. Nxf4 Qxg4 $1 ) 5... Kh8 ( 5... Kh6 $4 6. fxg5+ $18 ) ( 5... Qg6 $4 6. Nf8+ $18 ) 6. Qc3+ Kh7 7. Qc2+ Kh8 8. Qb2+ Kh7 9. Qb1+ Kh8 10. Qh1+ { White now has a checking candidate that was not possible before, and it wins. } 10... Qh7 11. Qa1+ Kg8 12. Qa8+ Kf7 13. Nxg5+ $18 { Winning the Queen and the game. } *