A puzzle by Satoshi, says Aoi
July 7, 2019, out of schedule because of the date. Block 77 gets two stages, the first and only one like that. Stage One pays 77 mBTC. The question is a link: Hal Finney's Bitcointalk post "Bitcoin and me". Format [solution], no TOMI field, and no hash digits. "You are on your own completely. Satoshi did not give any hint either."
The author's claim is big. Hal wrote that post, and Hal was Satoshi, so the post is Satoshi's puzzle. Stage One asks you to solve it. The author's solution would then become the question of Stage Two, worth 777 mBTC.
Recognize the signs
Players called it impossible. "We don't know where to look", wrote u/LiaVl. So the author gave three hints. Satoshi is an anagram of Thomas, roughly. The post itself says "I recognize the signs". And the genesis block puzzle, block 77 of the first run, was easier once you'd seen this one. As a bonus for that first block 77, the first hash digits too: 9dd.
After the author published the solution of Satoshi's puzzle, one thing was left: the format. It had been used in one earlier block, and the next blocks would point at it. Grycoin block 2 spelled it out on a small example: copy the whole text, flip the case of the letters that carry the signs.
Seven minutes after block 2
Grycoin block 2 was claimed at 14:02:10 UTC on August 3. Stage One followed at 14:09:57 UTC, to the same address. "Solved! it was easy after solving block 2", wrote u/puzzleponky. "There were some tricky bits though. I will wait for now before revealing the full solution."
The author didn't know those tricky bits either. "You are the only person knowing the full solution..." Nobody has posted it since, and players still ask in the thread. So the record has no key and the status is claimed.
Stage Two, the 777 mBTC block, is its own puzzle: the Real Big Block. As of October 2026, it's still unclaimed. Anyone?