A century after the Edo shogunate was founded, Fushimi had developed as a post town and riverside trading town, filled with travelers and goods, and demand for sake was increasing. Kasagiya, the old name of Gekkeikan, started keeping its books in kanjocho, or Japanese-style ledgers, in 1718. The kanjocho are daifukucho-format management records. Kasagiya's kanjocho is considered a rare historical artifact, thanks to being the oldest of its type used as a ledger by a sake brewery, and for the length of time it was in use.
The oldest remaining ledger at Gekkeikan is the one that was started in 1718. The subsequent records show how the company survived throughout the shogunate's Genjorei (order for reducing sake to be brewed), the fires of the Battle of Toba-Fushimi, and other trials.
Looking at the ledgers over the years, we can see entries for a range of sake types, including new sake, aged sake, mixed sake, simmered sake, and nanban-shu (South Asian liquor). While these days, brewing in winter is standard, we can see from this ledger how sake was originally brewed and sold year-round, such as for various Shinto feasts.
Listings in this ledger continued for nearly 190 years, until modern Western-style bookkeeping properly began in 1893.