6

What is the longest sequence of moves (by both White and Black) wherein White attempts to move one of their pieces from one square to another? Assume Black makes every move optimal towards the purpose of keeping White’s piece from reaching its intended square, but that it is nevertheless possible, in a finite number of moves, for White to achieve their purpose. If a complete response is impossible or impractical, partial/shorter responses are welcome. Both sides must have a king and pawns on the first rank of each side may do a double step.

For example, say that White’s goal is to get their King from e1 to g1 and can only achieve this through castling due to an unimpeded Black Rook on the second rank, but Black has an unimpeded Bishop on a6 controlling f1. White must remove the Bishop or the Rook from the diagonal in order to castle, which may take many moves.

Sorry if my question is vaguely worded or unclear in any way- I’ve never before written a chess-related problem. Also, feel free to edit the question or tags- all constructive criticism is welcomed.

  • 1
    All of the normal rules apply. As for both sides needing a king, I thought about it for a while, but I’ll say yes, both sides need a king. – Lieutenant Zipp Dec 30 '19 at 1:08
11

Thanks for the fun question, and welcome to CSE!

For this kind of construction problem, the king is obviously the piece to choose. Here is my offering of ** moves**. White wants to move their king to the b6, but it will take a long time.

EDIT 10/9/2020: The position that used to be here proved defective, so here is a new position, but unfortunately over a hundred moves had to be cut from the record.

[Title "me, chess.stackexchange.com 30/12/2019, White forces Black to let their king move to b7 in  336 moves"]
[FEN "Kb1n1b1k/b1p1pBp1/1pPpPpPp/pPpppppp/ppp1p1p1/8/8/pppppppp w - - 0 1"]

1. Be8 Kg8 2. Bd7 Kh8 3. Bc8 Kg8 4. Ba6 Kh8 5. Bb7 Kg8 6. Bc8 Kh8 7. Bd7 Kg8 8. Be8 Kh8 9. Bf7 a3 10. Be8 Kg8 11. Bd7 Kh8 12. Bc8 Kg8 13. Ba6 Kh8 14. Bb7 Kg8 15. Bc8 Kh8 16. Bd7 Kg8 17. Be8 Kh8 18. Bf7 a2 19. Be8 Kg8 20. Bd7 Kh8 21. Bc8 Kg8 22. Ba6 Kh8 23. Bb7 Kg8 24. Bc8 Kh8 25. Bd7 Kg8 26. Be8 Kh8 27. Bf7 a4 28. Be8 Kg8 29. Bd7 Kh8 30. Bc8 Kg8 31. Ba6 Kh8 32. Bb7 Kg8 33. Bc8 Kh8 34. Bd7 Kg8 35. Be8 Kh8 36. Bf7 a3 37. Be8 Kg8 38. Bd7 Kh8 39. Bc8 Kg8 40. Ba6 Kh8 41. Bb7 Kg8 42. Bc8 Kh8 43. Bd7 Kg8 44. Be8 Kh8 45. Bf7 b3 46. Be8 Kg8 47. Bd7 Kh8 48. Bc8 Kg8 49. Ba6 Kh8 50. Bb7 Kg8 51. Bc8 Kh8 52. Bd7 Kg8 53. Be8 Kh8 54. Bf7 b2 55. Be8 Kg8 56. Bd7 Kh8 57. Bc8 Kg8 58. Ba6 Kh8 59. Bb7 Kg8 60. Bc8 Kh8 61. Bd7 Kg8 62. Be8 Kh8 63. Bf7 c3 64. Be8 Kg8 65. Bd7 Kh8 66. Bc8 Kg8 67. Ba6 Kh8 68. Bb7 Kg8 69. Bc8 Kh8 70. Bd7 Kg8 71. Be8 Kh8 72. Bf7 c2 73. Be8 Kg8 74. Bd7 Kh8 75. Bc8 Kg8 76. Ba6 Kh8 77. Bb7 Kg8 78. Bc8 Kh8 79. Bd7 Kg8 80. Be8 Kh8 81. Bf7 c4 82. Be8 Kg8 83. Bd7 Kh8 84. Bc8 Kg8 85. Ba6 Kh8 86. Bb7 Kg8 87. Bc8 Kh8 88. Bd7 Kg8 89. Be8 Kh8 90. Bf7 c3 91. Be8 Kg8 92. Bd7 Kh8 93. Bc8 Kg8 94. Ba6 Kh8 95. Bb7 Kg8 96. Bc8 Kh8 97. Bd7 Kg8 98. Be8 Kh8 99. Bf7 d4 100. Be8 Kg8 101. Bd7 Kh8 102. Bc8 Kg8 103. Ba6 Kh8 104. Bb7 Kg8 105. Bc8 Kh8 106. Bd7 Kg8 107. Be8 Kh8 108. Bf7 d3 109. Be8 Kg8 110. Bd7 Kh8 111. Bc8 Kg8 112. Ba6 Kh8 113. Bb7 Kg8 114. Bc8 Kh8 115. Bd7 Kg8 116. Be8 Kh8 117. Bf7 d2 118. Be8 Kg8 119. Bd7 Kh8 120. Bc8 Kg8 121. Ba6 Kh8 122. Bb7 Kg8 123. Bc8 Kh8 124. Bd7 Kg8 125. Be8 Kh8 126. Bf7 d5 127. Be8 Kg8 128. Bd7 Kh8 129. Bc8 Kg8 130. Ba6 Kh8 131. Bb7 Kg8 132. Bc8 Kh8 133. Bd7 Kg8 134. Be8 Kh8 135. Bf7 d4 136. Be8 Kg8 137. Bd7 Kh8 138. Bc8 Kg8 139. Ba6 Kh8 140. Bb7 Kg8 141. Bc8 Kh8 142. Bd7 Kg8 143. Be8 Kh8 144. Bf7 d3 145. Be8 Kg8 146. Bd7 Kh8 147. Bc8 Kg8 148. Ba6 Kh8 149. Bb7 Kg8 150. Bc8 Kh8 151. Bd7 Kg8 152. Be8 Kh8 153. Bf7 e3 154. Be8 Kg8 155. Bd7 Kh8 156. Bc8 Kg8 157. Ba6 Kh8 158. Bb7 Kg8 159. Bc8 Kh8 160. Bd7 Kg8 161. Be8 Kh8 162. Bf7 e2 163. Be8 Kg8 164. Bd7 Kh8 165. Bc8 Kg8 166. Ba6 Kh8 167. Bb7 Kg8 168. Bc8 Kh8 169. Bd7 Kg8 170. Be8 Kh8 171. Bf7 e4 172. Be8 Kg8 173. Bd7 Kh8 174. Bc8 Kg8 175. Ba6 Kh8 176. Bb7 Kg8 177. Bc8 Kh8 178. Bd7 Kg8 179. Be8 Kh8 180. Bf7 e3 181. Be8 Kg8 182. Bd7 Kh8 183. Bc8 Kg8 184. Ba6 Kh8 185. Bb7 Kg8 186. Bc8 Kh8 187. Bd7 Kg8 188. Be8 Kh8 189. Bf7 f4 190. Be8 Kg8 191. Bd7 Kh8 192. Bc8 Kg8 193. Ba6 Kh8 194. Bb7 Kg8 195. Bc8 Kh8 196. Bd7 Kg8 197. Be8 Kh8 198. Bf7 f3 199. Be8 Kg8 200. Bd7 Kh8 201. Bc8 Kg8 202. Ba6 Kh8 203. Bb7 Kg8 204. Bc8 Kh8 205. Bd7 Kg8 206. Be8 Kh8 207. Bf7 f2 208. Be8 Kg8 209. Bd7 Kh8 210. Be8 Kg8 211. Bd7 Kh8 212. Bc8 Kg8 213. Ba6 Kh8 214. Bb7 Kg8 215. Bc8 Kh8 216. Bd7 Kg8 217. Be8 Kh8 218. Bf7 f5 219. Be8 Kg8 220. Bd7 Kh8 221. Bc8 Kg8 222. Ba6 Kh8 223. Bb7 Kg8 224. Bc8 Kh8 225. Bd7 Kg8 226. Be8 Kh8 227. Bf7 f4 228. Be8 Kg8 229. Bd7 Kh8 230. Bc8 Kg8 231. Ba6 Kh8 232. Bb7 Kg8 233. Bc8 Kh8 234. Bd7 Kg8 235. Be8 Kh8 236. Bf7 f3 237. Be8 Kg8 238. Bd7 Kh8 239. Bc8 Kg8 240. Ba6 Kh8 241. Bb7 Kg8 242. Bc8 Kh8 243. Bd7 Kg8 244. Be8 Kh8 245. Bf7 g3 246. Be8 Kg8 247. Bd7 Kh8 248. Bc8 Kg8 249. Ba6 Kh8 250. Bb7 Kg8 251. Bc8 Kh8 252. Bd7 Kg8 253. Be8 Kh8 254. Bf7 g2 255. Be8 Kg8 256. Bd7 Kh8 257. Bc8 Kg8 258. Ba6 Kh8 259. Bb7 Kg8 260. Bc8 Kh8 261. Bd7 Kg8 262. Be8 Kh8 263. Bf7 g4 264. Be8 Kg8 265. Bd7 Kh8 266. Bc8 Kg8 267. Ba6 Kh8 268. Bb7 Kg8 269. Bc8 Kh8 270. Bd7 Kg8 271. Be8 Kh8 272. Bf7 g3 273. Be8 Kg8 274. Bd7 Kh8 275. Bc8 Kg8 276. Ba6 Kh8 277. Bb7 Kg8 278. Bc8 Kh8 279. Bd7 Kg8 280. Be8 Kh8 281. Bf7 h4 282. Be8 Kg8 283. Bd7 Kh8 284. Bc8 Kg8 285. Ba6 Kh8 286. Bb7 Kg8 287. Bc8 Kh8 288. Bd7 Kg8 289. Be8 Kh8 290. Bf7 h3 291. Be8 Kg8 292. Bd7 Kh8 293. Bc8 Kg8 294. Ba6 Kh8 295. Bb7 Kg8 296. Bc8 Kh8 297. Bd7 Kg8 298. Be8 Kh8 299. Bf7 h2 300. Be8 Kg8 301. Bd7 Kh8 302. Bc8 Kg8 303. Ba6 Kh8 304. Bb7 Kg8 305. Bc8 Kh8 306. Bd7 Kg8 307. Be8 Kh8 308. Bf7 h5 309. Be8 Kg8 310. Bd7 Kh8 311. Bc8 Kg8 312. Ba6 Kh8 313. Bb7 Kg8 314. Bc8 Kh8 315. Bd7 Kg8 316. Be8 Kh8 317. Bf7 h4 318. Be8 Kg8 319. Bd7 Kh8 320. Bc8 Kg8 321. Ba6 Kh8 322. Bb7 Kg8 323. Bc8 Kh8 324. Bd7 Kg8 325. Be8 Kh8 326. Bf7 h3 327. Be8 Kg8 328. Bd7 Kh8 329. Bc8 Kg8 330. Ba6 Kh8 331. Bb7 Kg8 332. Bc8 Kh8 333. Bd7 Kg8 334. Be8 Kh8 335. Bf7 Nxc6 336. Kb7

As for a legal position, 111 moves is the longest I have come up with so far. White wants to move their king to any square as soon as possible.

[Title "me, chess.stackexchange.com 30/12/2019, White forces Black to allow a White king move in 111 moves"]
[FEN "5b1k/2p1pBp1/1pPpPpPp/1P1p4/8/7b/5n1P/3n2K1 w - - 0 1"]

1. Be8 Kg8 2. Bd7 Kh8 3. Bc8 Kg8 4. Ba6 Kh8 5. Bb7 Kg8 6. Bc8 Kh8 7. Bd7 Kg8 8. Be8 Kh8 9. Bf7 d4 10. Be8 Kg8 11. Bd7 Kh8 12. Bc8 Kg8 13. Ba6 Kh8 14. Bb7 Kg8 15. Bc8 Kh8 16. Bd7 Kg8 17. Be8 Kh8 18. Bf7 d3 19. Be8 Kg8 20. Bd7 Kh8 21. Bc8 Kg8 22. Ba6 Kh8 23. Bb7 Kg8 24. Bc8 Kh8 25. Bd7 Kg8 26. Be8 Kh8 27. Bf7 d2 28. Be8 Kg8 29. Bd7 Kh8 30. Bc8 Kg8 31. Ba6 Kh8 32. Bb7 Kg8 33. Bc8 Kh8 34. Bd7 Kg8 35. Be8 Kh8 36. Bf7 d5 37. Be8 Kg8 38. Bd7 Kh8 39. Bc8 Kg8 40. Ba6 Kh8 41. Bb7 Kg8 42. Bc8 Kh8 43. Bd7 Kg8 44. Be8 Kh8 45. Bf7 d4 46. Be8 Kg8 47. Bd7 Kh8 48. Bc8 Kg8 49. Ba6 Kh8 50. Bb7 Kg8 51. Bc8 Kh8 52. Bd7 Kg8 53. Be8 Kh8 54. Bf7 d3 55. Be8 Kg8 56. Bd7 Kh8 57. Bc8 Kg8 58. Ba6 Kh8 59. Bb7 Kg8 60. Bc8 Kh8 61. Bd7 Kg8 62. Be8 Kh8 63. Bf7 f5 64. Be8 Kg8 65. Bd7 Kh8 66. Bc8 Kg8 67. Ba6 Kh8 68. Bb7 Kg8 69. Bc8 Kh8 70. Bd7 Kg8 71. Be8 Kh8 72. Bf7 f4 73. Be8 Kg8 74. Bd7 Kh8 75. Bc8 Kg8 76. Ba6 Kh877. Bb7 Kg8 78. Bc8 Kh8 79. Bd7 Kg8 80. Be8 Kh8 81. Bf7 f3 82. Be8 Kg8 83. Bd7 Kh8 84. Bc8 Kg8 85. Ba6 Kh8 86. Bb7 Kg8 87. Bc8 Kh8 88. Bd7 Kg8 89. Be8 Kh8 90. Bf7 h5 91. Be8 Kg8 92. Bd7 Kh8 93. Bc8 Kg8 94. Ba6 Kh8 95. Bb7 Kg8 96. Bc8 Kh8 97. Bd7 Kg8 98. Be8 Kh8 99. Bf7 h4 100. Be8 Kg8 101. Bd7 Kh8 102. Bc8 Kg8 103. Ba6 Kh8 104. Bb7 Kg8 105. Bc8 Kh8 106. Bd7 Kg8 107. Be8 Kh8 108. Bf7 Bg2 109. h3 Ng4 110. hxg4 h3 111. Kh2
| improve this answer | |
  • 2
    What kind of game is this that the pawns aren't promoted when reaching the other side? – Mast Dec 30 '19 at 21:16
  • @Mast: it was legal in 1862 :) – Laska Oct 11 at 3:37
5

The best example I could find in PDB is this one:

[Title "Theodor Steudel: Problemkiste 66, Dec 1989, no. 2339. Za6 in 12"]
[StartFlipped "0"]
[fen "8/1p1p1p2/1P1P1P1P/8/p7/p1p1p1p1/2P1P1P1/k1K w K - 0 1"]

1.h7 a2 2.h8=N a3 3.Ng6 fxg6 4.f7 g5 5.f8=N g4 6.Ne6 dxe6
7.d7 e5 8.d8=N e4 9.Nc6 bxc6 10.b7 c5 11.b8=N c4 12.Na6

(Far greater lengths are possible in series-problems.)

| improve this answer | |
  • By looking in PDB. PDB uses e.g. "Za6 in 12" to mean "Show how White can move a unit to a6 within 12 moves, against any defence from Black". Stipulations like this may be preceded by "s" for "self" or "h" for "help", and further preceded by "ser-" for "series". Problems whose stipulations have any of those prefixes must be ignored because the OP wasn't about them. – Rosie F Jan 1 at 7:21
2

It depends on the exact position.

If white only has the king left, and in your position black only their rook, bishop and king, then it would take forever. Or at least untill the 50 move rule kicks in. Give black more pawns and each one of their moves could add another 50 to the duration.

With more pieces and or pawns it might take more or less time.

For example, let’s say it’s White to move the queen’s rook pawn to a8 from the normal starting position.

There is no way black can keep it from getting captured. Thus the pawn never gets to a8. The number of moves is equivalent to infinity.

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