Gambling Emperor Legend Zero: The Gambling Spirit Arc - Vol. 6 Ch. 44 - Conjecture

[MangaDex]

 

[PangTong]

This puzzle reminds me of Masquerade, a british picture book from the late 70s which contained obscure hints to the location of a real life treasure hidden by the author. The final location of the treasure was in the shadow of a monument that only indicated the correct digsite at a certain time of day during the spring or autumn equinox. The book was inexplicably popular in Japan even though the treasure was located in Britain and you had to know English to solve the clues. I wager that Fukumoto knows the story and might have even owned the book himself back in the day.

The story of Masquerade is super fascinating so I encourage people to look it up if you've never heard of it.