Endgame Studies

An endgame puzzle with a long solution is usually called a study.

Here's the most famous of them all. White can't catch the h-pawn nor force through their own passed pawn. But it's White to play and draw:

[Event "?"]
[Site "?"]
[Date "1922.??.??"]
[Round "?"]
[White "W"]
[Black "B"]
[Result "1/2-1/2"]
[Annotator "Reti"]
[SetUp "1"]
[FEN "7K/8/k1P5/7p/8/8/8/8 w - - 0 1"]
[PlyCount "7"]
[EventDate "1996.??.??"]

* 


Here's a really neat one with the same limited material. White to play and win, but I warn you now, distrust your first idea!

[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "No 16"]
[Black "?"]
[Result "*"]
[Annotator "Dedrle 1921"]
[SetUp "1"]
[FEN "8/8/5k2/8/p7/8/1PK5/8 w - - 0 1"]
[PlyCount "11"]

*

Solutions:

[Event "?"]
[Site "?"]
[Date "1922.??.??"]
[Round "?"]
[White "W"]
[Black "B"]
[Result "1/2-1/2"]
[Annotator "Reti"]
[SetUp "1"]
[FEN "7K/8/k1P5/7p/8/8/8/8 w - - 0 1"]
[PlyCount "7"]
[EventDate "1996.??.??"]

{[#]} 1. Kg7 h4 2. Kf6 h3 (2... Kb6 3. Ke5 Kxc6 4. Kf4) 3. Ke6 h2 4. c7 1/2-1/2


[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "No 16"]
[Black "?"]
[Result "*"]
[Annotator "Dedrle 1921"]
[SetUp "1"]
[FEN "8/8/5k2/8/p7/8/1PK5/8 w - - 0 1"]
[PlyCount "11"]

1. Kb1 (1. Kc3 a3 2. b4 (2. bxa3 Ke6 $11) 2... Ke5 3. Kb3 Kd5 4. Kxa3 Kc6 5.
Ka4 Kb6 6. b5 Kb7 7. Ka5 Ka7 8. b6+ Kb7 9. Kb5 Kb8 10. Kc6 Kc8 $11) 1... a3 (
1... Ke5 2. Ka2 Kd5 3. Ka3 Kc5 4. Kxa4 Kb6 5. Kb4 $18) 2. b3 Ke5 3. Ka2 Kd5 4.
Kxa3 Kc6 (4... Kc5 5. Ka4 Kb6 6. Kb4) 5. Ka4 (5. Kb4 Kb6 $11) 5... Kb6 6. Kb4
$18 *