At first, there was only a thatched hut there, which sheltered many tired hikers and fishermen, or people looking for medical remedies. Gradually, it transformed into a hot spring inn. It was even considered part of the Shikotsu-Toya National Park in 1949. After Sasaki died in 1947, his niece Yoshie Sasaki acquired the property and devoted all her time and energy to maintaining it. She was lovingly called "Marukoma's grandmother", and she's been immortalized through cafe Mémère (grandmother in French), which is located in the nearby Shikotsu Lake Onsen Shopping Arcade and directly managed by the ryokan. The Sapporo Olympics in 1972 brought with it the construction of roads and the boon of 24-hour electricity. After Yoshie's passing, Kinjiro took over the responsibility of the property and introduced thorough renovations in 1985. He worked with the local community to make Marukoma Onsen Ryokan what it is now. Over the years, it has hosted famous and important personalities, including members of the imperial family.

Bowing (ojigi): It's advisable to bow to show respect when greeting someone. It can also be done to show gratitude or convey an apology.
Shoe etiquette: You must remove your outside footwear before stepping on the elevated area of the genkan (entrance) and entering a house. You should also ensure not to step on the lower area of the genkan without your shoes on. Shoes must be kept facing the entrance. If you wear socks, they should be clean and without any holes.
Slipper etiquette: It's usually better to wear fresh socks or slippers inside the house, especially for formal situations. Make sure to remove your slippers before stepping into a room with tatami mats on the floor. There should also be a separate set of slippers for the washroom.
Dining etiquette: How you hold and place your chopsticks while dining is crucial. For example, they shouldn't be held upright when eating rice. You must also place them on a holder when you're not using them. It's good to say "Itadakimasu" before starting a meal and "Gochisousama deshita" after completing it.
Tipping etiquette: Tipping isn't a common practice in Japan and may be considered rude.
Luggage etiquette: Luggage, especially those with wheels, should be carried instead of being dragged across the floor as it might damage the tatami mats or wooden flooring.
Photography etiquette: Photography rules can change from place to place, so make sure to check for signs or ask the staff before taking pictures anywhere.
Queueing etiquette: Make sure to maintain queues and never cut in line.
Onsen etiquette: Some onsens don't allow tattoos, so check with the staff before getting into one. You must also shower and be clean before entering a shared onsen bath.
Bathing etiquette: Japanese baths include separate areas for washing while the tub itself is meant only for soaking. This means bathers must first wash, scrub, and rinse themselves before entering the bath tub.