In the 1920s, the current Yiran House was originally the guest rooms. The guests were assigned to stay in different rooms based on their numbers, the sizes of guest rooms, the equipment in the rooms, the budgets, or other factors.

The space of the "main room" might be 6-Tatami (about 9.72㎡) or 8-Tatami (about 12.96㎡) respectively in each Japanese guest room; some guest rooms might be accompanied with the "front rooms" of either 3-Tatami (about 4.86㎡) or 4-Tatami (about 6.48㎡). 

The adjacent two 8-Tatami main rooms could even be combined into a 16-Tatami (about 25.92㎡) large guest room, which could be adjusted according to the numbers of the guests and their needs. 

The "main rooms" were the space for major activities and sleep, and in the "front rooms" or under the corridors, there were usually "Oshiire" (押入), which were the cabinets or closets for storing beddings, pillows and luggages. The corridor-styled wooden passageways outside of the rooms, no matter watching from the delicate carved "Ranma" windows inside the rooms, or from the outlook of the integral-shaped design of Shoyintsukuri (書院造, a Japanese architectural form of a living room with an alcove), our guests can all profoundly feel the comfort and daintiness of the living quality in Kazan Hotel at that time.