user-1: What is the longest known stalemate your opponent in x-moves problem where the given stalemate is the fastest one from the initial position? A win is not possible, but stalemating your opponent so they can't move is, and any other draw takes at least as many moves. 
The solution does not have to be unique. The stalemating side will try to keep the game as short as possible, while the to-be-stalemated attempts to prolong it.
Here is an example of such a "stalemate your opponent" problem that is in 2 moves long.
[FEN "5k1K/8/7P/8/8/7b/8/8 b - - 0 1"]
[startflipped ""]

1... Bf5 2. h7 Kf7.

Another example is this with White to move. It is the record for White having only a king. 
[Title "CJ Morse, The Problemist 1985"]
[FEN "8/ppp1p3/4p3/4p3/8/8/1pp5/brk1K3 w - - 0 1"]

1. Ke2 e4 2. Ke1 e3 3. Ke2 e5 4. Ke1 e2 5. Kxe2 e4 6. Ke1 e3 7. Ke2 e6 8. Ke1 e2 9. Kxe2 e5 10. Ke1 e4 11. Ke2 e3 12. Ke1 e2 13. Kxe2 c6 14. Ke1 c5 15. Ke2 c4 16. Ke1 c3 17. Ke2 b6 18. Ke1 b5 19. Ke2 b4 20. Ke1 b3 21. Ke2 a6 22. Ke1 a5 23. Ke2 a4 24. Ke1 a3 25. Ke2 a2 26. Ke1

Can anyone find a longer fastest stalemate your opponent in x-moves problem than the 35-move one below that I created?

user15543: Here is a new record of 41 moves. I retooled the White knight checking cycle with a new scheme.
[Title "me, chess.stackexchange.com 8/25/2019, White Draws"]
[FEN "6r1/p1p1p1r1/p1p1p1q1/4pN1N/4n3/7K/4N1p1/R4Nbk w KQkq - 0 1"]

1. Nhg3+ Qxg3+ 2. N5xg3+ Rxg3+ 3. Nexg3+ Rxg3+ 4. Nxg3+ Nxg3 5. Kxg3 e4 6. Kh3 e3 7. Kg3 e2 8. Kh3 e1=Q 9. Rxe1 c5 10. Kg3 c4 11. Kh3 c3 12. Kg3 c2 13. Kh3 c1=Q 14. Rxc1 e5 15. Kg3 e4 16. Kh3 e3 17. Kg3 e2 18. Kh3 e1=Q 19. Rxe1 c6 20. Kg3 c5 21. Kh3 c4 22. Kg3 c3 23. Kh3 c2 24. Kg3 c1=Q 25. Rxc1 a5 26. Kh3 a4 27. Kg3 a3 28. Kh3 a2 29. Kg3 a1=Q 30. Rxa1 e6 31. Kh3 e5 32. Kg3 e4 33. Kh3 e3 34. Kg3 e2 35. Kh3 e1=Q 36. Rxe1 a6 37. Kg3 a5 38. Kh3 a4 39. Kg3 a3 40. Kh3 a2 41. Ra1


user7297: I'm sure this problem has been posed before, but let's see how far we can get. I assume White will try to stalemate Black as quickly as possible, and Black tries to stave it off as long as possible.
[FEN "8/p1p1p1p1/2p5/2p5/2p5/2K5/p3P1P1/k7 w - - 0 1"]

1. Kc2 e6 2. e4 e5 3. g4 g6 4. g5 c3 5. Kc1 c2 6. Kxc2 c4 7. Kc1 c3 8. Kc2 c5 9. Kc1 c2 10. Kxc2 c4 11. Kc1 c3 12. Kc2 c6 13. Kc1 c2 14. Kxc2 c5 15. Kc1 c4 16. Kc2 c3 17. Kc1 c2 18. Kxc2 a6 19. Kc1 a5 20. Kc2 a4 21. Kc1 a3 22. Kc2

White needs to go back and forth between c2 and c1 with his King, but can try to move his pawns forward to speed up the process. Black just pushes his pawns one step at a time.

user4270: I can't speak to whether this satisfies the (rather awkward) constraints you've put upon the problem, but the longest I was able to find with a rather cursory search was 201 moves:
[FEN "6K1/pn5n/2p3Q1/P1P5/Bp5p/p5p1/pbP3pr/rk5b w - - 0 1"]

1. c4+ Kc1 2. Qh6+ Kb1 3. Qxh7+ Kc1 4. Qh6+ Kb1 5. Qg6+ Kc1 6. Qg5+ Kb1 7. Qf5+ Kc1 8. Qf4+ Kb1 9. Qe4+ Kc1 10. Qe3+ Kb1 11. Qe1+ Bc1 12. Qxb4+ Bb2 13. Qe1+ Bc1 14. Qe4+ Kb2 15. Qe5+ Kb1 16. Qf5+ Kb2 17. Qf6+ Kb1 18. Qg6+ Kb2 19. Qg7+ Kb1 20. Qxb7+ Bb2 21. Qh7+ Kc1 22. Qh6+ Kb1 23. Qg6+ Kc1 24. Qg5+ Kb1 25. Qf5+ Kc1 26. Qf4+ Kb1 27. Qe4+ Kc1 28. Qe3+ Kb1 29. Qg1+ Bc1 30. a6 Kb2 31. Qd4+ Kb1 32. Qe4+ Kb2 33. Qe5+ Kb1 34. Qf5+ Kb2 35. Qf6+ Kb1 36. Qg6+ Kb2 37. Qg7+ Kb1 38. Qb7+ Bb2 39. Qh7+ Kc1 40. Qh6+ Kb1 41. Qg6+ Kc1 42. Qg5+ Kb1 43. Qf5+ Kc1 44.Qf4+ Kb1 45. Qe4+ Kc1 46. Qe3+ Kb1 47. Qg1+ Bc1 48. Kf8 Kb2 49. Qd4+ Kb1 50. Qe4+ Kb2 51. Qe5+ Kb1 52. Qf5+ Kb2 53. Qf6+ Kb1 54. Qg6+ Kb2 55. Qg7+ Kb1 56. Qb7+ Bb2 57. Qh7+ Kc1 58. Qh6+ Kb1 59. Qg6+ Kc1 60. Qg5+ Kb1 61. Qf5+ Kc1 62. Qf4+ Kb1 63. Qe4+ Kc1 64. Qe3+ Kb1 65. Qg1+ Bc1 66. Ke8 Kb2 67. Qd4+ Kb1 68. Qe4+ Kb2 69. Qe5+ Kb1 70. Qf5+ Kb2 71. Qf6+ Kb1 72. Qg6+ Kb2 73. Qg7+ Kb1 74. Qb7+ Bb2 75. Qh7+ Kc1 76. Qh6+ Kb1 77. Qg6+ Kc1 78. Qg5+ Kb1 79. Qf5+ Kc1 80. Qf4+ Kb1 81. Qe4+ Kc1 82. Qe3+ Kb1 83. Qg1+ Bc1 84. Kd8 Kb2 85. Qd4+ Kb1 86. Qe4+ Kb2 87. Qe5+ Kb1 88. Qf5+ Kb2 89. Qf6+ Kb1 90. Qg6+ Kb2 91. Qg7+ Kb1 92. Qb7+ Bb2 93. Qh7+ Kc1 94. Qh6+ Kb1 95. Qg6+ Kc1 96. Qg5+ Kb1 97. Qf5+ Kc1 98. Qf4+ Kb1 99. Qe4+ Kc1 100. Qe3+ Kb1101. Qg1+ Bc1 102. Kc8 Kb2 103. Qd4+ Kb1 104. Qe4+ Kb2 105. Qe5+ Kb1 106. Qf5+ Kb2 107. Qf6+ Kb1 108. Qg6+ Kb2 109. Qg7+ Kb1 110. Qb7+ Bb2 111. Qh7+ Kc1 112.Qh6+ Kb1 113. Qg6+ Kc1 114. Qg5+ Kb1 115. Qf5+ Kc1 116. Qf4+ Kb1 117. Qe4+ Kc1 118. Qe3+ Kb1 119. Qg1+ Bc1 120. Kb8 Kb2 121. Qd4+ Kb1 122. Qe4+ Kb2 123. Qe5+ Kb1 124. Qf5+ Kb2 125. Qf6+ Kb1 126. Qg6+ Kb2 127. Qg7+ Kb1 128. Qb7+ Bb2 129.Qh7+ Kc1 130. Qh6+ Kb1 131. Qg6+ Kc1 132. Qg5+ Kb1 133. Qf5+ Kc1 134. Qf4+ Kb1 135. Qe4+ Kc1 136. Qe3+ Kb1 137. Qg1+ Bc1 138. Kxa7 Kb2 139. Qd4+ Kb1 140. Qe4+ Kb2 141. Qe5+ Kb1 142. Qf5+ Kb2 143. Qf6+ Kb1 144. Qg6+ Kb2 145. Qg7+ Kb1146. Qb7+ Bb2 147. Qh7+ Kc1 148. Qh6+ Kb1 149. Qg6+ Kc1 150. Qg5+ Kb1 151. Qf5+ Kc1 152. Qf4+ Kb1 153. Qe4+ Kc1 154. Qe3+ Kb1 155. Qg1+ Bc1 156. Kb8 Kb2 157. Qd4+ Kb1 158. Qe4+ Kb2 159. Qe5+ Kb1 160. Qf5+ Kb2 161. Qf6+ Kb1 162. Qg6+ Kb2 163. Qg7+ Kb1 164. Qb7+ Bb2 165. Qh7+ Kc1 166. Qh6+ Kb1 167. Qg6+ Kc1 168. Qg5+ Kb1 169. Qf5+ Kc1 170. Qf4+ Kb1 171. Qe4+ Kc1 172. Qe3+ Kb1 173. Qg1+ Bc1 174. a7 Kb2 175. Qd4+ Kb1 176. Qe4+ Kb2 177. Qe5+ Kb1 178. Qf5+ Kb2 179. Qf6+ Kb1 180. Qg6+ Kb2 181. Qg7+ Kb1 182. Qb7+ Bb2 183. Qh7+ Kc1 184. Qh6+ Kb1 185. Qg6+ Kc1 186. Qg5+ Kb1 187. Qf5+ Kc1 188. Qf4+ Kb1 189. Qe4+ Kc1 190. Qe3+ Kb1 191. Qg1+ Bc1 192. a8=Q Kb2 193. Qd4+ Kb1 194. Qb7+ Bb2 195. Qh7+ Kc1 196. Qh6+ Kb1 197. Qg1+ Bc1 198. Qd2 Rh3 199. Bxc6 Rh2 200. Bd7 Rh3 201. Bxh3

White plays c4+, then continually checks the black king (who alternates between shuttling back and forth between b1 and c1 with the bishop on b2, and shuttling between b1 and b2 with the bishop on c1) while maneuvering the WQ from g6 first to capture the Nh7, then the Pb4, then the Nb7, then eventually to check black at g1 and force 29...Bc1.  Play then goes 30. Pa6 Kb2 and White executes a zigzag up to g7, then checks on b7 (forcing 38...Bb2 once again), then checks on h7 and zigzags back to play 47. Qg1+ and force Bc1 again, taking another 'free move' to play 48. Kf8.
This same maneuver (zigzag up to g7, check on b7 inducing Bb2, zigzag to check on g1, forcing Bc1, then take a 'free move' when Black's best play is Kb2) repeats as White plays 66. Ke8, 84. Kd8, 102. Kc8, 120. Kb8, 138. Kxa7, 156. Kb8, 174. Pa7, and 192. Pa8Q; play concludes with Qd4+, Q-b7-h7-h6+, Qg1+, and 198. Qd2 Rh3 199. Bxc6 Rg3, 200. Bd7 Rh3 201. Bxh3 stalemate.
(This problem comes out of The Problemist, by CJ Morse.)

user19415: Aloril has created what he calls “mobility chess” and generated up to 5-man tablebase for it. It just so happens that it generates shortest forced stalemates when there is one and there is no possible mating sequence.
Here are the extracted statistics provided for the longest forced stalemate sequences of 3, 4, and 5 unit positions.
3 man:
[Title "KPvK, stalemate, 42 ply"]
[StartFlipped "0"]
[FEN "8/8/8/8/8/1k6/7P/K7 b - - 0 1"]

1...Kc4 2. Kb1 Kd3 3. Kc1!! Ke4 4. Kd1 Kd3 5. Ke1! Ke3! 6. Kf1! Kf3! 7. Kg1! Kf4! 8. Kf2 Kg4! 9. Kg2! Kh4! 10. h3! Kh5! 11. Kg3! Kg5! 12. h4+! Kf5 13. Kf3!! Kf6! 14. Kf4 Kg6! 15. Kg4! Kg7 16. Kg5! Kf7 17. h5! Kg7! 18. h6+! Kf7 19. Kf5!! Kf8! 20. Kf6 Kg8!! 21. Kg6! Kh8!! 22. h7! * 

4 man:
[Title "KPvKP, stalemate, 53 ply"]
[FEN "K7/8/5p2/8/8/8/1P6/5k2 w - - 0 1"]

1. b4!! f5 2. b5!! f4 3. b6!! f3 4. b7!! f2 5. b8=Q!! Kg2! 6. Qb2 Kg1! 7. Qd4! Kg2! 8. Qg4+! Kh1 9. Qf3+ Kg1!! 10. Qg3+! Kf1! 11. Ka7 Ke2! 12. Qg2 Ke1!! 13. Qe4+! Kd1 14. Qd3+ Ke1!! 15. Qe3+! Kf1!! 16. Kb6! Kg2! 17. Qe2 Kg1!! 18. Qg4+! Kh1 19. Qf3+ Kg1!! 20. Qg3+! Kf1! 21. Kc5! Ke2!! 22. Qh2! Kf3!! 23. Qh5+! Kg2!! 24. Qg4+! Kh1 25. Qf3+ Kg1!! 26. Qg3+! Kh1!! 27. Qxf2! * 

5 man:
[Title "KQPvKQ, stalemate, 210 ply"]
[StartFlipped "0"]
[FEN "3q4/7Q/2K5/8/7k/8/4P3/8 b - - 0 1"]

1...Kg5!! 2. Qg7+!! Kh4! 3. Qh6+! Kg4! 4. Qe6+ Kf4!! 5. Qf7+! Ke5! 6. Qh5+! Kd4!! 7. Qg4+!! Kc3! 8. Qf3+!! Kb4 9. Qe4+ Kc3!! 10. Qe3+! Kc2!! 11. Qf3! Qa8+ 12. Kd6!! Qd8+! 13. Ke5! Qc7+ 14. Kf5! Qd7+ 15. Kf4 Qc7+! 16. Kg4! Qg7+!! 17. Kh3 Qh8+! 18. Kg2 Qg7+!! 19. Kf2! Qd4+! 20. Qe3! Qh4+! 21. Kg1 Qg4+! 22. Kf1! Qc4! 23. Qe5! Kd2! 24. Qg5+! Kd1! 25. Qd8+! Kc2! 26. Qf6! Kb3! 27. Kf2!! Qc5+! 28. Kg2!! Kb4 29. Qe6!! Kb5! 30. Kf3! Qh5+! 31. Kf4! Qh4+!! 32. Qg4! Qf2+! 33. Ke4!! Kb6 34. Qe6+! Kc7!! 35. Qc4+! Kb7! 36. Ke5! Qh2+! 37. Kd5!! Qh5+! 38. Kd6!! Qh2+! 39. Ke7! Qe5+! 40. Qe6!! Qg7+!! 41. Kd6! Qc7+! 42. Kd5!! Qd8+! 43. Ke5! Qg5+!! 44. Kd6! Qg3+!! 45. Kd7! Qg7+!! 46. Qe7! Qd4+!! 47. Ke6+!! Kc6 48. Qe8+!! Kc5 49. Qf8+! Kc6! 50. Qf3+! Kc7! 51. Qg3+! Kc6! 52. Qg2+! Kc7! 53. Qh2+! Kc6! 54. Qh1+! Kc5! 55. Qc1+!! Kb6! 56. Qb1+!! Ka7! 57. Qh7+! Ka8! 58. Qf5! Qb6+!! 59. Kf7! Qc7+! 60. Kg6! Qc6+! 61. Kg5! Qg2+! 62. Qg4!! Qd5+!! 63. Kh4! Qh1+! 64. Kg3! Qg1+! 65. Kf3! Qf1+! 66. Ke4! Qb1+! 67. Kf4! Qb4+ 68. Kf3! Qb3+ 69. e3! Qd1+! 70. Kg3! Qg1+! 71. Kf4! Qh2+! 72. Kf3! Qh1+! 73. Qg2! Qh4 74. Qg8+! Kb7! 75. Qf7+! Kc8! 76. Qf5+! Kd8!! 77. Qf8+! Kd7!! 78. Qg7+! Kc6! 79. Qg6+!! Kb5! 80. Qf5+! Kb6! 81. e4! Kc6! 82. Qe6+ Kc5 83. e5! Qd4! 84. Qf6! Kb5! 85. Qg5! Kc6! 86. Qe3! Qa1! 87. Kf4! Qa2 88. Qe4+! Kd7! 89. Qf5+! Ke8! 90. Kg5! Qb3! 91. Qg6+ Kd7 92. Qf6! Qa2 93. Kh6! Qe6! 94. Kh7 Qe7+! 95. Kg6! Qe6! 96. Kh6! Qa2 97. Kg7! Qe6!! 98. Qf7+! Qe7!! 99. Kg6!! Kd8!! 100. Qxe7+! Kxe7!! 101. Kf5! Kf7!! 102. e6+! Ke7! 103. Ke5!! Ke8!! 104. Kd6 Kd8!! 105. e7+! Ke8!! 106. Ke6!! *


user-1: The following thirty five move position is the longest position I could create. 
White basically checks with four knights on c2 before blocking the black pawns with the king and knight on h1 while keeping the black king boxed in on a1. I tried extending this by adding another white knight on a3 to check on c2 but a black queen or black bishop cannot be added to capture on c2 since black still has eight pawns and there would be no square to place a black knight on to capture on c2. 
[FEN "8/p1p2p1p/5pbp/8/qN1N4/4N2p/pr1r4/k1K1N2N w - - 0 1"]

  1. Nbc2 Bc2 2. N4c2 Rbc2 3. N3c2 Rc2 4. Nc2 Qc2 5. Kc2 h2 6. Nf2 h5 7. Nh1 h4 8. Nf2 h3 9. Nh1 h6 10. Nf2 h5 11. Nh1 h4 12. Nf2 f5 13. Nh1 f4 14. Nf2 f3 15. Nh1 f6 16. Nf2 f5 17. Nh1 f4 18. Nf2 a6 19. Nh1 a5 20. Nf2 a4 21. Nh1 a3 22. Nf2 c6 23. Nh1 c5 24. Nf2 c4 25. Nh1 c3 26. Nf2 h1=Q 27. Nh1 h2 28. Nf2 h3 29. Nh1 f2 30. Nf2 f3 31. Nh1 f2 32. Nf2 h1=Q 33. Nh1 h2 34. Nf2 h1=Q 35. Nh1


-1: <p>What is the longest known stalemate your opponent in x-moves problem where the given stalemate is the fastest one from the initial position? A win is not possible, but stalemating your opponent so they can't move is, and any other draw takes at least as many moves. </p>

<p>The solution does not have to be unique. The stalemating side will try to keep the game as short as possible, while the to-be-stalemated attempts to prolong it.</p>

<p>Here is an example of such a "stalemate your opponent" problem that is in 2 moves long.</p>

<pre><code>[FEN "5k1K/8/7P/8/8/7b/8/8 b - - 0 1"]
[startflipped ""]

1... Bf5 2. h7 Kf7.
</code></pre>

<p>Another example is this with White to move. It is the record for White having only a king. </p>

<pre><code>[Title "CJ Morse, The Problemist 1985"]
[FEN "8/ppp1p3/4p3/4p3/8/8/1pp5/brk1K3 w - - 0 1"]

1. Ke2 e4 2. Ke1 e3 3. Ke2 e5 4. Ke1 e2 5. Kxe2 e4 6. Ke1 e3 7. Ke2 e6 8. Ke1 e2 9. Kxe2 e5 10. Ke1 e4 11. Ke2 e3 12. Ke1 e2 13. Kxe2 c6 14. Ke1 c5 15. Ke2 c4 16. Ke1 c3 17. Ke2 b6 18. Ke1 b5 19. Ke2 b4 20. Ke1 b3 21. Ke2 a6 22. Ke1 a5 23. Ke2 a4 24. Ke1 a3 25. Ke2 a2 26. Ke1
</code></pre>

<p>Can anyone find a longer fastest stalemate your opponent in x-moves problem than the 35-move one below that I created?</p>
 15543: <p>Here is a new record of <strong>41 moves.</strong> I retooled the White knight checking cycle with a new scheme.</p>
<pre><code>[Title &quot;me, chess.stackexchange.com 8/25/2019, White Draws&quot;]
[FEN &quot;6r1/p1p1p1r1/p1p1p1q1/4pN1N/4n3/7K/4N1p1/R4Nbk w KQkq - 0 1&quot;]

1. Nhg3+ Qxg3+ 2. N5xg3+ Rxg3+ 3. Nexg3+ Rxg3+ 4. Nxg3+ Nxg3 5. Kxg3 e4 6. Kh3 e3 7. Kg3 e2 8. Kh3 e1=Q 9. Rxe1 c5 10. Kg3 c4 11. Kh3 c3 12. Kg3 c2 13. Kh3 c1=Q 14. Rxc1 e5 15. Kg3 e4 16. Kh3 e3 17. Kg3 e2 18. Kh3 e1=Q 19. Rxe1 c6 20. Kg3 c5 21. Kh3 c4 22. Kg3 c3 23. Kh3 c2 24. Kg3 c1=Q 25. Rxc1 a5 26. Kh3 a4 27. Kg3 a3 28. Kh3 a2 29. Kg3 a1=Q 30. Rxa1 e6 31. Kh3 e5 32. Kg3 e4 33. Kh3 e3 34. Kg3 e2 35. Kh3 e1=Q 36. Rxe1 a6 37. Kg3 a5 38. Kh3 a4 39. Kg3 a3 40. Kh3 a2 41. Ra1
</code></pre>
 7297: <p>I'm sure this problem has been posed before, but let's see how far we can get. I assume White will try to stalemate Black as quickly as possible, and Black tries to stave it off as long as possible.</p>

<pre><code>[FEN "8/p1p1p1p1/2p5/2p5/2p5/2K5/p3P1P1/k7 w - - 0 1"]

1. Kc2 e6 2. e4 e5 3. g4 g6 4. g5 c3 5. Kc1 c2 6. Kxc2 c4 7. Kc1 c3 8. Kc2 c5 9. Kc1 c2 10. Kxc2 c4 11. Kc1 c3 12. Kc2 c6 13. Kc1 c2 14. Kxc2 c5 15. Kc1 c4 16. Kc2 c3 17. Kc1 c2 18. Kxc2 a6 19. Kc1 a5 20. Kc2 a4 21. Kc1 a3 22. Kc2
</code></pre>

<p>White needs to go back and forth between c2 and c1 with his King, but can try to move his pawns forward to speed up the process. Black just pushes his pawns one step at a time.</p>
 4270: <p>I can't speak to whether this satisfies the (rather awkward) constraints you've put upon the problem, but the longest I was able to find with a rather cursory search was 201 moves:</p>

<pre><code>[FEN "6K1/pn5n/2p3Q1/P1P5/Bp5p/p5p1/pbP3pr/rk5b w - - 0 1"]

1. c4+ Kc1 2. Qh6+ Kb1 3. Qxh7+ Kc1 4. Qh6+ Kb1 5. Qg6+ Kc1 6. Qg5+ Kb1 7. Qf5+ Kc1 8. Qf4+ Kb1 9. Qe4+ Kc1 10. Qe3+ Kb1 11. Qe1+ Bc1 12. Qxb4+ Bb2 13. Qe1+ Bc1 14. Qe4+ Kb2 15. Qe5+ Kb1 16. Qf5+ Kb2 17. Qf6+ Kb1 18. Qg6+ Kb2 19. Qg7+ Kb1 20. Qxb7+ Bb2 21. Qh7+ Kc1 22. Qh6+ Kb1 23. Qg6+ Kc1 24. Qg5+ Kb1 25. Qf5+ Kc1 26. Qf4+ Kb1 27. Qe4+ Kc1 28. Qe3+ Kb1 29. Qg1+ Bc1 30. a6 Kb2 31. Qd4+ Kb1 32. Qe4+ Kb2 33. Qe5+ Kb1 34. Qf5+ Kb2 35. Qf6+ Kb1 36. Qg6+ Kb2 37. Qg7+ Kb1 38. Qb7+ Bb2 39. Qh7+ Kc1 40. Qh6+ Kb1 41. Qg6+ Kc1 42. Qg5+ Kb1 43. Qf5+ Kc1 44.Qf4+ Kb1 45. Qe4+ Kc1 46. Qe3+ Kb1 47. Qg1+ Bc1 48. Kf8 Kb2 49. Qd4+ Kb1 50. Qe4+ Kb2 51. Qe5+ Kb1 52. Qf5+ Kb2 53. Qf6+ Kb1 54. Qg6+ Kb2 55. Qg7+ Kb1 56. Qb7+ Bb2 57. Qh7+ Kc1 58. Qh6+ Kb1 59. Qg6+ Kc1 60. Qg5+ Kb1 61. Qf5+ Kc1 62. Qf4+ Kb1 63. Qe4+ Kc1 64. Qe3+ Kb1 65. Qg1+ Bc1 66. Ke8 Kb2 67. Qd4+ Kb1 68. Qe4+ Kb2 69. Qe5+ Kb1 70. Qf5+ Kb2 71. Qf6+ Kb1 72. Qg6+ Kb2 73. Qg7+ Kb1 74. Qb7+ Bb2 75. Qh7+ Kc1 76. Qh6+ Kb1 77. Qg6+ Kc1 78. Qg5+ Kb1 79. Qf5+ Kc1 80. Qf4+ Kb1 81. Qe4+ Kc1 82. Qe3+ Kb1 83. Qg1+ Bc1 84. Kd8 Kb2 85. Qd4+ Kb1 86. Qe4+ Kb2 87. Qe5+ Kb1 88. Qf5+ Kb2 89. Qf6+ Kb1 90. Qg6+ Kb2 91. Qg7+ Kb1 92. Qb7+ Bb2 93. Qh7+ Kc1 94. Qh6+ Kb1 95. Qg6+ Kc1 96. Qg5+ Kb1 97. Qf5+ Kc1 98. Qf4+ Kb1 99. Qe4+ Kc1 100. Qe3+ Kb1101. Qg1+ Bc1 102. Kc8 Kb2 103. Qd4+ Kb1 104. Qe4+ Kb2 105. Qe5+ Kb1 106. Qf5+ Kb2 107. Qf6+ Kb1 108. Qg6+ Kb2 109. Qg7+ Kb1 110. Qb7+ Bb2 111. Qh7+ Kc1 112.Qh6+ Kb1 113. Qg6+ Kc1 114. Qg5+ Kb1 115. Qf5+ Kc1 116. Qf4+ Kb1 117. Qe4+ Kc1 118. Qe3+ Kb1 119. Qg1+ Bc1 120. Kb8 Kb2 121. Qd4+ Kb1 122. Qe4+ Kb2 123. Qe5+ Kb1 124. Qf5+ Kb2 125. Qf6+ Kb1 126. Qg6+ Kb2 127. Qg7+ Kb1 128. Qb7+ Bb2 129.Qh7+ Kc1 130. Qh6+ Kb1 131. Qg6+ Kc1 132. Qg5+ Kb1 133. Qf5+ Kc1 134. Qf4+ Kb1 135. Qe4+ Kc1 136. Qe3+ Kb1 137. Qg1+ Bc1 138. Kxa7 Kb2 139. Qd4+ Kb1 140. Qe4+ Kb2 141. Qe5+ Kb1 142. Qf5+ Kb2 143. Qf6+ Kb1 144. Qg6+ Kb2 145. Qg7+ Kb1146. Qb7+ Bb2 147. Qh7+ Kc1 148. Qh6+ Kb1 149. Qg6+ Kc1 150. Qg5+ Kb1 151. Qf5+ Kc1 152. Qf4+ Kb1 153. Qe4+ Kc1 154. Qe3+ Kb1 155. Qg1+ Bc1 156. Kb8 Kb2 157. Qd4+ Kb1 158. Qe4+ Kb2 159. Qe5+ Kb1 160. Qf5+ Kb2 161. Qf6+ Kb1 162. Qg6+ Kb2 163. Qg7+ Kb1 164. Qb7+ Bb2 165. Qh7+ Kc1 166. Qh6+ Kb1 167. Qg6+ Kc1 168. Qg5+ Kb1 169. Qf5+ Kc1 170. Qf4+ Kb1 171. Qe4+ Kc1 172. Qe3+ Kb1 173. Qg1+ Bc1 174. a7 Kb2 175. Qd4+ Kb1 176. Qe4+ Kb2 177. Qe5+ Kb1 178. Qf5+ Kb2 179. Qf6+ Kb1 180. Qg6+ Kb2 181. Qg7+ Kb1 182. Qb7+ Bb2 183. Qh7+ Kc1 184. Qh6+ Kb1 185. Qg6+ Kc1 186. Qg5+ Kb1 187. Qf5+ Kc1 188. Qf4+ Kb1 189. Qe4+ Kc1 190. Qe3+ Kb1 191. Qg1+ Bc1 192. a8=Q Kb2 193. Qd4+ Kb1 194. Qb7+ Bb2 195. Qh7+ Kc1 196. Qh6+ Kb1 197. Qg1+ Bc1 198. Qd2 Rh3 199. Bxc6 Rh2 200. Bd7 Rh3 201. Bxh3
</code></pre>

<p>White plays c4+, then continually checks the black king (who alternates between shuttling back and forth between b1 and c1 with the bishop on b2, and shuttling between b1 and b2 with the bishop on c1) while maneuvering the WQ from g6 first to capture the Nh7, then the Pb4, then the Nb7, then eventually to check black at g1 and force 29...Bc1.  Play then goes 30. Pa6 Kb2 and White executes a zigzag up to g7, then checks on b7 (forcing 38...Bb2 once again), then checks on h7 and zigzags back to play 47. Qg1+ and force Bc1 again, taking another 'free move' to play 48. Kf8.</p>

<p>This same maneuver (zigzag up to g7, check on b7 inducing Bb2, zigzag to check on g1, forcing Bc1, then take a 'free move' when Black's best play is Kb2) repeats as White plays 66. Ke8, 84. Kd8, 102. Kc8, 120. Kb8, 138. Kxa7, 156. Kb8, 174. Pa7, and 192. Pa8Q; play concludes with Qd4+, Q-b7-h7-h6+, Qg1+, and 198. Qd2 Rh3 199. Bxc6 Rg3, 200. Bd7 Rh3 201. Bxh3 stalemate.</p>

<p>(This problem comes out of <em>The Problemist</em>, by CJ Morse.)</p>
 19415: <p>Aloril has created what he calls <a href="https://tcec-chess.com/puzzle/rules.html" rel="nofollow noreferrer">“mobility chess”</a> and generated up to 5-man tablebase for it. It just so happens that it generates shortest forced stalemates when there is one and there is no possible mating sequence.</p>

<p>Here are the extracted statistics provided for the longest forced stalemate sequences of 3, 4, and 5 unit positions.</p>

<p>3 man:</p>

<pre><code>[Title "KPvK, stalemate, 42 ply"]
[StartFlipped "0"]
[FEN "8/8/8/8/8/1k6/7P/K7 b - - 0 1"]

1...Kc4 2. Kb1 Kd3 3. Kc1!! Ke4 4. Kd1 Kd3 5. Ke1! Ke3! 6. Kf1! Kf3! 7. Kg1! Kf4! 8. Kf2 Kg4! 9. Kg2! Kh4! 10. h3! Kh5! 11. Kg3! Kg5! 12. h4+! Kf5 13. Kf3!! Kf6! 14. Kf4 Kg6! 15. Kg4! Kg7 16. Kg5! Kf7 17. h5! Kg7! 18. h6+! Kf7 19. Kf5!! Kf8! 20. Kf6 Kg8!! 21. Kg6! Kh8!! 22. h7! * 
</code></pre>

<p>4 man:</p>

<pre><code>[Title "KPvKP, stalemate, 53 ply"]
[FEN "K7/8/5p2/8/8/8/1P6/5k2 w - - 0 1"]

1. b4!! f5 2. b5!! f4 3. b6!! f3 4. b7!! f2 5. b8=Q!! Kg2! 6. Qb2 Kg1! 7. Qd4! Kg2! 8. Qg4+! Kh1 9. Qf3+ Kg1!! 10. Qg3+! Kf1! 11. Ka7 Ke2! 12. Qg2 Ke1!! 13. Qe4+! Kd1 14. Qd3+ Ke1!! 15. Qe3+! Kf1!! 16. Kb6! Kg2! 17. Qe2 Kg1!! 18. Qg4+! Kh1 19. Qf3+ Kg1!! 20. Qg3+! Kf1! 21. Kc5! Ke2!! 22. Qh2! Kf3!! 23. Qh5+! Kg2!! 24. Qg4+! Kh1 25. Qf3+ Kg1!! 26. Qg3+! Kh1!! 27. Qxf2! * 
</code></pre>

<p>5 man:</p>

<pre><code>[Title "KQPvKQ, stalemate, 210 ply"]
[StartFlipped "0"]
[FEN "3q4/7Q/2K5/8/7k/8/4P3/8 b - - 0 1"]

1...Kg5!! 2. Qg7+!! Kh4! 3. Qh6+! Kg4! 4. Qe6+ Kf4!! 5. Qf7+! Ke5! 6. Qh5+! Kd4!! 7. Qg4+!! Kc3! 8. Qf3+!! Kb4 9. Qe4+ Kc3!! 10. Qe3+! Kc2!! 11. Qf3! Qa8+ 12. Kd6!! Qd8+! 13. Ke5! Qc7+ 14. Kf5! Qd7+ 15. Kf4 Qc7+! 16. Kg4! Qg7+!! 17. Kh3 Qh8+! 18. Kg2 Qg7+!! 19. Kf2! Qd4+! 20. Qe3! Qh4+! 21. Kg1 Qg4+! 22. Kf1! Qc4! 23. Qe5! Kd2! 24. Qg5+! Kd1! 25. Qd8+! Kc2! 26. Qf6! Kb3! 27. Kf2!! Qc5+! 28. Kg2!! Kb4 29. Qe6!! Kb5! 30. Kf3! Qh5+! 31. Kf4! Qh4+!! 32. Qg4! Qf2+! 33. Ke4!! Kb6 34. Qe6+! Kc7!! 35. Qc4+! Kb7! 36. Ke5! Qh2+! 37. Kd5!! Qh5+! 38. Kd6!! Qh2+! 39. Ke7! Qe5+! 40. Qe6!! Qg7+!! 41. Kd6! Qc7+! 42. Kd5!! Qd8+! 43. Ke5! Qg5+!! 44. Kd6! Qg3+!! 45. Kd7! Qg7+!! 46. Qe7! Qd4+!! 47. Ke6+!! Kc6 48. Qe8+!! Kc5 49. Qf8+! Kc6! 50. Qf3+! Kc7! 51. Qg3+! Kc6! 52. Qg2+! Kc7! 53. Qh2+! Kc6! 54. Qh1+! Kc5! 55. Qc1+!! Kb6! 56. Qb1+!! Ka7! 57. Qh7+! Ka8! 58. Qf5! Qb6+!! 59. Kf7! Qc7+! 60. Kg6! Qc6+! 61. Kg5! Qg2+! 62. Qg4!! Qd5+!! 63. Kh4! Qh1+! 64. Kg3! Qg1+! 65. Kf3! Qf1+! 66. Ke4! Qb1+! 67. Kf4! Qb4+ 68. Kf3! Qb3+ 69. e3! Qd1+! 70. Kg3! Qg1+! 71. Kf4! Qh2+! 72. Kf3! Qh1+! 73. Qg2! Qh4 74. Qg8+! Kb7! 75. Qf7+! Kc8! 76. Qf5+! Kd8!! 77. Qf8+! Kd7!! 78. Qg7+! Kc6! 79. Qg6+!! Kb5! 80. Qf5+! Kb6! 81. e4! Kc6! 82. Qe6+ Kc5 83. e5! Qd4! 84. Qf6! Kb5! 85. Qg5! Kc6! 86. Qe3! Qa1! 87. Kf4! Qa2 88. Qe4+! Kd7! 89. Qf5+! Ke8! 90. Kg5! Qb3! 91. Qg6+ Kd7 92. Qf6! Qa2 93. Kh6! Qe6! 94. Kh7 Qe7+! 95. Kg6! Qe6! 96. Kh6! Qa2 97. Kg7! Qe6!! 98. Qf7+! Qe7!! 99. Kg6!! Kd8!! 100. Qxe7+! Kxe7!! 101. Kf5! Kf7!! 102. e6+! Ke7! 103. Ke5!! Ke8!! 104. Kd6 Kd8!! 105. e7+! Ke8!! 106. Ke6!! *
</code></pre>
 -1: <p>The following thirty five move position is the longest position I could create. </p>

<p>White basically checks with four knights on c2 before blocking the black pawns with the king and knight on h1 while keeping the black king boxed in on a1. I tried extending this by adding another white knight on a3 to check on c2 but a black queen or black bishop cannot be added to capture on c2 since black still has eight pawns and there would be no square to place a black knight on to capture on c2. </p>

<pre><code>[FEN "8/p1p2p1p/5pbp/8/qN1N4/4N2p/pr1r4/k1K1N2N w - - 0 1"]

  1. Nbc2 Bc2 2. N4c2 Rbc2 3. N3c2 Rc2 4. Nc2 Qc2 5. Kc2 h2 6. Nf2 h5 7. Nh1 h4 8. Nf2 h3 9. Nh1 h6 10. Nf2 h5 11. Nh1 h4 12. Nf2 f5 13. Nh1 f4 14. Nf2 f3 15. Nh1 f6 16. Nf2 f5 17. Nh1 f4 18. Nf2 a6 19. Nh1 a5 20. Nf2 a4 21. Nh1 a3 22. Nf2 c6 23. Nh1 c5 24. Nf2 c4 25. Nh1 c3 26. Nf2 h1=Q 27. Nh1 h2 28. Nf2 h3 29. Nh1 f2 30. Nf2 f3 31. Nh1 f2 32. Nf2 h1=Q 33. Nh1 h2 34. Nf2 h1=Q 35. Nh1
</code></pre>
