White to move and checkmate in 268 moves.

The $100 version of Gothic Vortex is capable of annoucing wins in endgames from a distance of up to 268 moves. This includes the complete set of every possible way to place a total of 5 different pieces on the 10x8 board. The endgame shown above is the longest win featuring King + Queen + Pawn vs. King + Queen. The solution is shown below. Where you see an exclamation mark (!) that means the associated move is the only move to win in that position.

1. Qe2! Qg8+ 2. Ka7! Qg7+ 3. Ka6! Qa1+ 4. Kb7 Qb2+ 5. Kc6 Qf6+ 6. Kc5 Qf5+ 7. Kd6 Qf8+ 8. Kd7! Qf7+ 9. Qe7 Qd5+ 10. Qd6! Qb7+ 11. Ke6 Qe4+ 12. Kf6 Qf3+ 13. Ke5 Qe2+ 14. Kf5 Qf3+ 15. Qf4 Qd5+ 16. Kf6 Qc6+ 17. Ke5 Qb5+ 18. Ke4 Qb1+ 19. Ke3 Qe1+ 20. Kd3 Qc1 21. Ke2 Qc2 22. Ke3 Qc1 23. Kf2 Qc2 24. Kg3 Qg6+ 25. Kf3 Qd3+ 26. Qe3 Qf5+ 27. Kg3 Qi5+ 28. Kg4 Qi6+ 29. Kf4 Qf6+ 30. Kg3! Qj6+ 31. Kf3! Qi6+ 32. Kf2 Qi5+ 33. Ke2 Qb5+ 34. Ke1 Qb1+ 35. Kf2 Qa2 36. Kg3 Qg8+ 37. Kf4 Qj8+ 38. Kf5 Qf8+ 39. Ke6 Qc8+ 40. Kd6 Qd8+ 41. Kc6 Qa8+ 42. Kb5 Qb7+ 43. Ka5 Qa8+ 44. Kb4 Qb7+ 45. Ka3 Qa6+ 46. Kb2 Qb5+ 47. Qb3 Qe5+ 48. Qc3! Qb5+ 49. Ka3 Qa6+ 50. Kb4 Qb6+ 51. Kc4 Qc6+ 52. Kd4 Qd6+ 53. Ke4 Qg6+ 54. Kd5 Qg8+ 55. Kc5 Qc8+ 56. Kd4 Qg8 57. Qc6+ Ki2 58. Qd7+! Ki3 59. Kc3 Qa2 60. Qd6 Qa1+ 61. Kc4 Qc1+ 62. Kb5 Qb1+ 63. Qb4 Qd3+ 64. Kc6! Ki2 65. Qi4+ Kh2 66. Qh5+! Kg1 67. Qd5! Qa6+ 68. Kd7! Qa7+ 69. Ke6! Qb6+ 70. Kf5 Qf2+ 71. Ke5 Qe2+ 72. Kf6 Qf2+ 73. Ke7 Qa7+ 74. Qd7 Qc5+ 75. Qd6! Qg5+ 76. Ke6 Qg6+ 77. Kd7! Qg4+ 78. Kc6 Qa4+ 79. Kb7 Qe4+ 80. Kb6 Qb1+ 81. Ka6 Qa2+ 82. Kb7 Qf7+ 83. Kc6 Qf3+ 84. Qd5 Qf6+ 85. Kc5 Qa6 86. Kb4! Kf2 87. Qb5! Qe6 88. Kc3! Kf3 89. Qd3+ Kg2 90. Qc4! Qe1 91. Qg4+ Kh2 92. Qf4+ Kg2 93. Kb2 Qe2 94. Qi4+ Kh2 95. Qh4+ Ki2 96. Kc2 Kj3 97. Kc3 Qf3+ 98. d3 Qe3 99. Qd4 Qh6 100. Qd5 Qe3 101. Kc4 Qa7 102. Qc5 Qa2+ 103. Kc3! Qa1+ 104. Kd2 Qa2+ 105. Ke3 Qe6+ 106. Kd4 Qg4+ 107. Kc3! Qg3 108. Qf5 Qc7+ 109. Kd2 Qd6 110. Ke3 Qh6+ 111. Ke4 Qc6+ 112. Qd5 Qg6+ 113. Kf3 Qf6+ 114. Ke2 Qj2+ 115. Ke3 Qe7+ 116. Kd4 Qh4+ 117. Kc5 Qe7+ 118. Kb6 Qf6+ 119. Kb5 Qb2+ 120. Kc6 Qc3+ 121. Kd7 Qg7+ 122. Ke8 Qh8+ 123. Ke7 Qh4+ 124. Kd7 Qh3+ 125. Kc7 Qg3+ 126. Kc6 Qg6+ 127. Kc5 Qa6 128. Qf3+ Ki4 129. Qg4+ Ki5 130. Qd7 Qa5+ 131. Qb5! Qc7+ 132. Kd5 Qd8+ 133. Ke6+! Ki4 134. Qd5 Qg8+ 135. Ke5 Qg5+ 136. Kd4 Qg7+ 137. Kc4 Qc7+ 138. Qc5 Qf7+ 139. Kc3 Qf3 140. Qd6 Kh3 141. Qe6+! Kg3 142. Kc4 Qf1 143. Qg8+! Kh4 144. Qd5! Kg4 145. Kb5! Kg3 146. Qg5+ Kh2 147. Qe3 Kg2 148. Kb4 Qb1+ 149. Kc5! Qc2+ 150. Kd6! Qc8 151. d4 Qd8+ 152. Kc5 Qc7+ 153. Kb4 Qb6+ 154. Kc3 Qa5+ 155. Kc4 Qa6+ 156. Kc5 Qa5+ 157. Kc6 Qa8+ 158. Kd7 Qd5+ 159. Ke7 Qb7+ 160. Kf8 Qb8+ 161. Kg7 Qc7+ 162. Kg6 Qc6+ 163. Kg5 Qa8 164. Qe2+ Kg1 165. Qe5 Qj8+ 166. Kg6 Qj6+ 167. Kf7 Qj3+ 168. Ke7 Qi3+ 169. Kd7 Qh3+ 170. Kc7 Qc3+ 171. Qc5 Qg3+ 172. Qd6 Qc3+ 173. Kd7 Qh3+ 174. Kc6 Kh1 175. d5 Qh8 176. Kb5 Qh7 177. Kb6 Qh8 178. Qe7 Qb2+ 179. Kc6 Qc2+ 180. Qc5 Qe4 181. Kb6 Qb1+ 182. Qb5 Qg6+ 183. Kc5 Qf5 184. Qe2 Ki1 185. Qe1+ Kh2 186. Qh4+ Ki1 187. Kd4 Qf1 188. Qg3+ Kj2 189. Qj6+ Ki1 190. Qi6+ Kj2 191. d6 Qa1+ 192. Kd5 Qa8+ 193. Ke5 Qb8 194. Qj5+ Ki2 195. Qg2+ Ki1 196. Qc6 Qh8+ 197. Ke6 Qh3+ 198. Ke7 Qh4+ 199. Kd7 Qh7+ 200. Kc8 Qg8+ 201. Kc7 Qg3 202. Qc4 Ki2 203. Qb4 Qe5 204. Kc6 Qe6 205. Qb2+ Ki1 206. Qc1+ Ki2 207. Qi7+ Kj3 208. Qj7+ Ki4 209. Kc7 Qc4+ 210. Kd8! Qg8+ 211. Kd7 Qg3 212. Qe7 Kj4 213. Qj2+ Ki5 214. Qd2 Ki6 215. Kc6 Qf3+ 216. Kc7 Qf5 217. Qe2+ Kj6 218. Qc4 Qa5+ 219. Kb7 Qf5 220. Qc6 Qb1+ 221. Kc7 Qi1 222. Qd5 Ki6 223. Qf5 Kj6 224. Kd7 Qg3 225. Ke6 Qb3+ 226. Kf6 Qi3+ 227. Kf7 Qi7+ 228. Kf8 Qh8+ 229. Ke7 Qi7+ 230. Qf7 Qc1 231. Qf6+ Ki7 232. d7 Qc5+ 233. Ke8 Qb5 234. Qc3 Ki8 235. Ke7 Qg5+ 236. Kd6 Qh6+ 237. Kc7 Qf4+ 238. Kb7 Qe4+ 239. Kb6 Qb1+ 240. Kc7 Qi1+ 241. Kc8 Qi2 242. Qd3+ Kj8 243. Qg6 Qh3 244. Qg8+ Ki7 245. Qg7+ Kj6 246. Qf6+ Ki5 247. Kc7 Qh7 248. Qd4 Ki6 249. Kb7 Kj7 250. Ka8 Qh1+ 251. Ka7 Qh7 252. Qd1+ Ki7 253. Qc1+ Kj6 254. Qc7 Qh8 255. d8Q Qa1+ 256. Kb8 Qb1+ 257. Qb6+ Qxb6+ 258. Qxb6+! Ki5 259. Qb4 Ki6 260. Qi4+ Kh6 261. Kc7 Kg5 262. Kc6 Kf6 263. Qh5 Kg7 264. Kd5 Kf6 265. Kd6 Kg7 266. Ke6 Kg8 267. Kf6 Kf8 268. Qh8# checkmate

Of course, there are many other interesting endgames in the 5-piece tablebase.