Longest individual notation?

Because the maximum number of turns that the game can possibly go to is 4,800 (actually no! Black's pawns can also move before they get captured, but this will not bring the number of moves to 10,000, but let's assume the final capture or pawn move is on move 4,750 so that the final move number is 4,800), the notation may be like 4,800...Kh5 (by this point en passant is not possible and captures would have been completed) or earlier in the game may be 4,750. h8=Q+.

Unfortunately by move 50 a pawn must be pushed or something must be captured, and moving knight around in 50 different configurations is possible, but not easy to achieve (you must remember the exact positions to not fall into repetitions). It is hard to reach notations like 1000...hxg5e.p.+ though, but that's probably the longest notation (by the number of spaces occupied) that you can find.

Haha ok cool. It's not like I expect these to actually come up in games. Thank you for all this work though

This is not an individual notation, but is one complete end-game (just posting it for fun). It is the longest known forced mate (546 moves). Here it is:

1... Rd7+ 2. Kc3 $1 2... Ng5 3. Qf1+ $1 3... Bf3 4. Qc1+ $1 4... Kf5 5. Kb2
$1 5... Rb7+ 6. Ka3 Ra7+ 7. Kb4 Rb7+ 8. Ka5 Ra7+ 9. Kb6 Rb7+ 10. Ka6 Re7 11.
Qf1 Re6+ 12. Ka7 Re7+ 13. Kb8 Re8+ 14. Kc7 Re3 15. Kc8 Rc3+ 16. Kb8 $1 16...
Kf4 17. Qg1 $1 17... Ne4 18. Nf1 $1 18... Rb3+ 19. Ka7 $1 19... Rd3 20.
Qh2+ $1 20... Kf5 21. Kb8 Nf6 22. Nd2 $1 22... Bd5 23. Qf2+ $1 23... Ke5
24. Qe2+ Kd4 25. Ka7 Nd7 26. Qg4+ $1 26... Kc5 27. Qg1+ $1 27... Kb4 28.
Qb1+ $1 28... Kc3 29. Qc1+ Kd4 30. Qb2+ Kc5 31. Qc2+ $1 31... Kd4 32. Qa4+
Kc5 33. Qa5+ Kd4 34. Qb4+ Ke5 35. Ka6 Kf5 36. Kb5 Ne5 37. Qb1 Kf6 38. Qf1+ Bf3
39. Qf2 $1 39... Ke6 40. Qh2 $1 40... Bc6+ 41. Kb4 $1 41... Bd5 42. Kc5 Kf6
43. Kb5 Ke6 44. Qh6+ Kf5 45. Nf1 Bc6+ 46. Kb4 Rd4+ 47. Kb3 Rd3+ 48. Ka2 Bd5+
49. Kb1 $1 49... Nc4 50. Qh5+ $1 50... Kf6 51. Qh4+ Ke6 52. Ng3 $1 52...
Rb3+ 53. Kc1 $1 53... Rc3+ 54. Kd1 Re3 55. Nf1 $1 55... Ra3 56. Qf4 Kd7 57.
Ke1 Kc6 58. Qh6+ Kc5 59. Kf2 Rb3 60. Qh8 Kc6 61. Qa1 Kc5 62. Kg1 Ra3 63. Qb1
$1 63... Kc6 64. Kh2 Rf3 65. Qc1 Kc5 66. Qa1 $1 66... Kd6 67. Qe1 Rb3 68.
Qc1 Rf3 69. Kg1 Ra3 70. Qc2 Rf3 71. Qh2+ Kc6 72. Qh4 Kb5 73. Qe7 Kb6 74. Qb4+
Kc6 75. Qe1 Ra3 76. Qf2 Rf3 77. Qd4 Kd6 78. Qh4 Kc5 79. Nh2 Ra3 80. Ng4 Ra1+
81. Kf2 $1 81... Ra2+ 82. Kg3 $1 82... Ra3+ 83. Kf4 Rf3+ 84. Kg5 $1 84...
Be6 85. Nf6 $1 85... Ne5 86. Nh5 Rf5+ 87. Kh6 $1 87... Ng4+ 88. Kg6 $1
88... Ne5+ 89. Kg7 Rf7+ 90. Kh6 $1 90... Ng4+ 91. Kg5 Ne5 92. Qa4 Rf5+ 93.
Kh6 $1 93... Bc4 94. Qa5+ Kd4 95. Qb6+ Kd5 96. Qd8+ Ke4 97. Qd1 Ke3 98. Qc1+
Kd4 99. Ng3 Rf6+ 100. Kh5 Kd5 101. Kh4 Rg6 102. Kh3 Bd3 103. Qf4 Rg8 104. Qb4
Ke6 105. Kh2 Kd7 106. Qb6 Rg6 107. Qb8 Ke6 108. Qf8 Rf6 109. Qg8+ Kd6 110. Kg2
Rg6 111. Qf8+ Kd5 112. Kh3 Bb5 113. Qa3 Bc6 114. Kg2 Rf6 115. Kh2 Nf3+ 116.
Kh3 Rh6+ 117. Kg2 $1 117... Nd4 118. Qe7 Kc4+ 119. Kg1 $1 119... Rg6 120.
Qf7+ Re6 121. Qf4 Kd3 122. Qf1+ Kc3 123. Qc1+ Kb4 124. Kh2 Rf6 125. Kh3 Bd7+
126. Kg2 $1 126... Bc6+ 127. Kh2 Rf3 128. Qd1 Kc5 129. Nh5 Kd5 130. Qh1 Ke5
131. Qe1+ Kd5 132. Qe7 Kc4 133. Qc7 Kc3 134. Nf4 Kc4 135. Qb8 Rc3 136. Qb6 Be4
137. Qa7 Bc6 138. Qa6+ Kc5 139. Nd3+ Kd6 140. Nb2 Rb3 141. Nd1 Nf3+ 142. Kg2
Nd4+ 143. Kf2 Rf3+ 144. Ke1 Kd5 145. Qb6 Kc4 146. Qa7 Bb5 147. Nf2 Nc2+ 148.
Kf1 Bc6 149. Qa6+ Kc5 150. Qa2 Nd4 151. Kg1 $1 151... Rf5 152. Kh2 Rh5+ 153.
Kg3 $1 153... Rg5+ 154. Kf4 $1 154... Rf5+ 155. Kg4 Bf3+ 156. Kh4 Rh5+ 157.
Kg3 $1 157... Rg5+ 158. Kf4 Rf5+ 159. Ke3 $1 159... Re5+ 160. Kd3 Be2+ 161.
Kd2 $1 161... Kb4 162. Qg8 Bb5 163. Qg4 Kc4 164. Nd1 Re2+ 165. Kc1 $1 165...
Rc2+ 166. Kb1 $1 166... Rd2 167. Qc8+ Bc6 168. Qg8+ $1 168... Kb4 169. Nb2
Be4+ 170. Ka2 $1 170... Nb5 171. Qb3+ $1 171... Ka5 172. Ka1 $1 172... Bd5
173. Qa4+ $1 173... Kb6 174. Qb4 $1 174... Rd4 175. Qe1 Re4 176. Qd2 Rd4
177. Qe3 Ka5 178. Nd3 Be4 179. Qe1+ Kb6 180. Nf2 Bf3 181. Kb2 Be2 182. Qg1 Ka5
183. Qh1 Bc4 184. Qe1+ Kb6 185. Qe3 Ka5 186. Ne4 Rd3 187. Qg5 Bd5 188. Nd2 Ka4
189. Kc2 Bc4 190. Qh6 Rd6 191. Qh4 Rd4 192. Qf6 Kb4 193. Kc1 Bd5 194. Kd1 Rd3
195. Ke2 Rd4 196. Ke1 Ka5 197. Nf1 Bb3 198. Kf2 Rd6 199. Qf4 Rd4 200. Qf5 Rd6
201. Qe4 Bf7 202. Qc2 Ka6 203. Ng3 Kb6 204. Kg1 Bg6 205. Qf2+ Ka6 206. Nf1 Be4
207. Qf4 Rd4 208. Qc1 Ka5 209. Kh2 Ka6 210. Ne3 Ka5 211. Kh3 Bd3 212. Kg3 Ka4
213. Qb2 Be4 214. Kg4 Bd5+ 215. Kg5 Bb3 216. Qa1+ Kb4 217. Ng4 Rd5+ 218. Ne5
Kc5 219. Kf6 Rd1 220. Qb2 Rd6+ 221. Ke7 Bc4 222. Qa1 Be6 223. Qg1+ Kb4 224.
Qe1+ Ka4 225. Kf6 Bg8+ 226. Kf5 Bb3 227. Kg5 Rd5 228. Qa1+ Kb4 229. Kf4 Rd1
230. Qb2 Rd6 231. Kg4 Nc3 232. Qc1 Rd4+ 233. Kh5 Rd5 234. Qe1 Bc2 235. Qh4+
Be4 236. Qe7+ Kb3 237. Kh6 Rd4 238. Kg7 Kc2 239. Qf6 Rb4 240. Kh6 Rb7 241. Ng4
Rd7 242. Ne3+ Kd3 243. Qf1+ Kd4 244. Ng4 Rd5 245. Qg1+ Kd3 246. Qf2 Rf5 247.
Qe3+ Kc4 248. Qd2 Kb3 249. Qd7 Ra5 250. Ne3 Ra6+ 251. Kh5 Ra4 252. Kg5 Ka3
253. Kh6 Kb3 254. Qd6 Ka2 255. Qd8 Kb3 256. Qg8+ Kb2 257. Qb8+ Ka3 258. Qb6
Rb4 259. Qf6 Kb3 260. Qf7+ Ka3 261. Nc4+ Ka4 262. Qe6 Kb3 263. Nb6+ Kc2 264.
Qd6 Rb5 265. Nc4 Kb3 266. Nd2+ Kc2 267. Nf1 Kb3 268. Qd4 Bg2 269. Nd2+ Kc2
270. Nc4 Kb3 271. Qf4 Bd5 272. Nd2+ Kc2 273. Qf2 Nd1 274. Qh2 Kc3 275. Nf1 Kb3
276. Kg7 Rb7+ 277. Kh8 Rb5 278. Qg3+ Nc3 279. Ne3 Ra5 280. Qe5 Rb5 281. Nf5
Rc5 282. Kg7 Rc8 283. Kh6 Rc6+ 284. Kh5 Rc5 285. Kh4 Ra5 286. Kg3 Ra4 287. Ne3
Rd4 288. Qb8+ Rb4 289. Qd8 Rd4 290. Qb6+ Rb4 291. Qg6 Be4 292. Qe6+ Ka3 293.
Kf2 Ka4 294. Qd7+ Ka3 295. Ke1 Nb5 296. Qd8 Nc3 297. Qf6 Kb3 298. Qf7+ Ka3
299. Kd2 Nb5 300. Nc4+ Kb3 301. Nd6+ Ka4 302. Qa2+ Na3 303. Ke3 Bc6 304. Nf5
Re4+ 305. Kf3 Kb4 306. Qb2+ Ka5 307. Qd2+ Ka4 308. Kg3 Nc4 309. Qd8 Kb4 310.
Qf8+ Kb3 311. Qc5 Ba8 312. Qg1 Kb4 313. Qb1+ Kc5 314. Qb8 Bd5 315. Kf2 Kc6
316. Qa8+ Kc5 317. Qd8 Re5 318. Qc7+ Kb4 319. Nd4 Kc3 320. Qc5 Kd3 321. Nb5 $1
321... Re2+ 322. Kg3 $1 322... Re3+ 323. Kf4 Re4+ 324. Kg5 Re5+ 325. Kf6
Re6+ 326. Kg7 Ne3 327. Qd4+ Ke2 328. Kf8 Kf3 329. Qh4 Re4 330. Nd4+ Kg2 331.
Qg5+ Kf2 332. Nf5 Bb3 333. Qg3+ Ke2 334. Qh2+ Kd3 335. Qd6+ Nd5 336. Qg6 Nf4
337. Qg3+ Kc2 338. Qh2+ Kd3 339. Nd6 Ne6+ 340. Ke7 Re3 341. Nf5 Re2 342. Qg3+
Kc2 343. Kf6 Kb2 344. Qd6 Rc2 345. Qe5+ Ka2 346. Nd6 Nc5 347. Qe1 Kb2 348. Ke7
Rc1 349. Qe3 Rc2 350. Qd4+ Ka2 351. Nb5 Re2+ 352. Kf6 Rc2 353. Qb4 Rf2+ 354.
Kg6 Rg2+ 355. Kh5 Rh2+ 356. Kg4 Rc2 357. Qa3+ Kb1 358. Kf5 Rc4 359. Kg6 Rg4+
360. Kh6 Rh4+ 361. Kg5 Rc4 362. Kh5 Rc2 363. Qa8 Kb2 364. Qf3 Rc4 365. Qe2+
Kc1 366. Qe5 Ne4 367. Kg6 Bc2 368. Kf7 Ra4 369. Qd5 Kb2 370. Nd4 Kc3 371. Ne2+
Kb2 372. Qe5+ Ka2 373. Kg7 Ra7+ 374. Kh6 Ra6+ 375. Kh5 Ra4 376. Qe6+ Ka3 377.
Qe7+ Kb2 378. Qg7+ Kb3 379. Qb7+ Rb4 380. Nc1+ Ka3 381. Qe7 Ka4 382. Qa7+ Kb5
383. Qb7+ Kc4 384. Qf7+ Kb5 385. Ne2 Rc4 386. Qb7+ Kc5 387. Nf4 Nc3 388. Ne6+
Kd6 389. Nd8 Kc5 390. Kh6 Be4 391. Ne6+ Kd6 392. Qb8+ Kc6 393. Qa7 Kd6 394.
Nd4 Ke5 395. Qg7+ Kd6 396. Nb3 Bd5 397. Qg3+ Ke6 398. Qg6+ Kd7 399. Nd4 Kc7
400. Qa6 Kb8 401. Qd6+ Ka8 402. Qd7 Rc5 403. Kg6 Bb7 404. Nb3 Rc6+ 405. Kg5
Ne4+ 406. Kf4 $1 406... Rf6+ 407. Ke3 Rf3+ 408. Kd4 Rf6 409. Qd8+ Ka7 410.
Ke3 Re6 411. Qa5+ Kb8 412. Nd4 Re8 413. Kd3 Ba6+ 414. Kc2 Rc8+ 415. Kb2 Ka7
416. Nb3 Nd6 417. Qa4 Nb7 418. Qd4+ Kb8 419. Qe5+ Ka7 420. Qe6 Rc7 421. Qe3+
Kb8 422. Qe5 Bf1 423. Ka3 Bh3 424. Kb4 Bd7 425. Qf4 Kc8 426. Qf8+ $1 426...
Nd8 427. Nc5 Rc6 428. Kc4 Rb6 429. Kc3 Rb5 430. Kd2 Ra5 431. Qd6 Bc6 432. Ke3
Ra7 433. Qe5 Rf7 434. Kd2 Rf2+ 435. Ke1 Rf7 436. Qh8 Ra7 437. Qf6 Rc7 438.
Qf5+ Bd7 439. Qe5 Bc6 440. Kf1 Rf7+ 441. Kg1 Ra7 442. Qf6 Rc7 443. Qg6 Re7
444. Qg4+ Bd7 445. Qg3 Be8 446. Qg5 Ra7 447. Qg4+ Bd7 448. Qd4 Bc6 449. Ne4
Re7 450. Nd6+ Kc7 451. Qc5 Re6 452. Nb5+ Kc8 453. Nd4 Rh6 454. Nf5 Re6 455.
Ne7+ Kc7 456. Qa5+ Kd7 457. Qa7+ Bb7 458. Nf5 $1 458... Kc8 459. Qd4 Bc6 460.
Qg7 Re1+ 461. Kf2 $1 461... Re6 462. Ne7+ Kb8 463. Kf1 Be4 464. Kg1 Bc6 465.
Nf5 Nb7 466. Qg8+ Re8 467. Qg3+ Kc8 468. Qg7 Kd8 469. Qf6+ Kd7 470. Qf7+ Kd8
471. Ng7 Re1+ 472. Kf2 Re7 473. Qf8+ Kd7 474. Nf5 Re8 475. Qf7+ Kd8 476. Kg3
Bd7 477. Qf6+ Kc7 478. Ne7 Rd8 479. Nd5+ Kb8 480. Nb6 Be8 481. Nc4 Rc8 482.
Qe6 Rd8 483. Kf3 Ka8 484. Qf6 Kb8 485. Kf2 Rc8 486. Qe6 Bd7 487. Qe5+ $1
487... Rc7 488. Kg3 Nc5 489. Qb2+ Rb7 490. Qh8+ Bc8 491. Nd6 Rc7 492. Qb2+ Nb7
493. Nb5 Rc5 494. Kh4 Be6 495. Qe2 Nd8 496. Nd4 Bc4 497. Qe8 Rc8 498. Qd7 Ba6
499. Qd5 Bb7 500. Qd6+ Ka8 501. Qb6 Nc6 502. Nb5 Rd8 503. Nc7+ Kb8 504. Ne6
Rd1 505. Kg5 Ka8 506. Nc5 Nd8 507. Qc7 Ka7 508. Kf4 Ka8 509. Ke3 Ka7 510. Nd7
Nc6 511. Qb6+ Ka8 512. Nc5 Nd8 513. Nd3 Nc6 514. Ke2 Rxd3 515. Kxd3 {[%t bLon]
Mate in 32:} 515... Kb8 516. Qb5 Na7 517. Qb4 Nc8 518. Kd4 Na7 519. Qf8+ Nc8
520. Qc5 Ba8 521. Ke5 Bg2 522. Ke6 Bh3+ 523. Kf6 Bg2 524. Qe5+ Ka7 525. Qc3
Nb6 526. Qa1+ Kb7 527. Ke6 Bh3+ 528. Kd6 Nc8+ 529. Kc5 Kc7 530. Qa4 Bd7 531.
Qa5+ Kb7 532. Qd8 Bc6 533. Qf6 Bd7 534. Qe5 Na7 535. Qd6 Bc6 536. Qe7+ Kb8
537. Qd8+ Kb7 538. Qb6+ Ka8 539. Qb4 Bb7 540. Kb6 Kb8 541. Qd6+ Ka8 542. Qc5
Nc6 543. Qf8+ Nb8 544. Qe7 Nd7+ 545. Qxd7 Bc8 546. Qxc8# 1-0

You can see the end game at this post:

https://www.chess.com/forum/view/endgames/who-wins-from-this-puzzle

 Yeah wow! Nice one!

Haha let me know how you do it

How many characters long are the full set of notations in post #26? Maybe 100,000?

Apparently that section has approximately 7700. That might include spaces, but does include the extra notes (like mate in 32). 
But I think we should stick with characters per ply - 7 (more with a move number).

And also the sequence has $1 in it alot

Yes, I pulled the game (546-move forced mate) from a forum about the Lomonosov databases (supercomputers where the 7 piece chess tablebases were produced).

I don't know what the $1 symbols are for.

I agree the main goal should be characters per ply. But it might be hard to find more than 7 (plus move number). It's hard to imaging that going up by a lot.

{1}{.}{_}{Q}{h}{x}{f}{8}{#}{_}{1}{-}{0}

If there was a queen on h8 it would make the notation longer.

Maybe [cxd6 e.p.++] compare to:

            [Qa1xe5+] since you cant make notation except queen moves that need to use a very spesific initial position of the pieces you want to move

So, I think the answer is simply use the longest formal notation,that is e.p. (en passant) and ++(double check).My answer is (pawn captures piece using en passant while making double check).

 dxc6e.p.+ N#

Or if using the long chess notation, its definitely still using e.p and ++ , so the answer is still same: (pawn captures piece using en passant while making double check) Example: c5xd6 e.p. ++

(fortunately pawn can double check while making en passant or Qa1xe5+ will slightly win since c5 is one letter /number shorter that Qa1 and double (.) is slightly shorter than one letter or number.) 

Comparison:

..

a

..

1

what is N# ?

Novelty, Checkmate.

Mshd1xc2#!

in albania Msh represents the queen

and seriously in online notation just simply delivers mate using pawn's en passant so u can get "1-0" that is so long compares to ++ and e.p.