The haisen was a basin containing water to wash sake cups. In Japan, people believe that drinking sake out of the same cup is to understand how each person feels. This exchange is called kenshu, and refers to both offering and being offered a sake cup. After drinking all the sake you are offered, you turn the cup upside down, rinse it with water, and return it for the other person to drink from. The haisen basin acts as the go-between in this ritual.
Haisen used in high-class restaurants would have refined, elegant pictures on them. Originally, large basins or bowls would have been used instead of a haisen. These gradually changed to ones made of porcelain or lacquer so as to look better at banquets featuring sake. The tin haisen Gekkeikan holds in its collection has a design of the Rising Sun flag and cherry blossoms on the background, overlaid with the Gekkeikan logo.
Haisen decorated with maki-e lacquer would probably have been carefully placed on stands when set out at banquets. In the same way, there were also stands for the sake cups themselves, which were known as haidai (stands). Japan's staple food has been rice for all of its recorded history. Sake takes more effort to make than anything else made of rice, so it is offered in the center of the Kamidana (household Shinto altar) as the most precious item there. A beautiful culture has arisen through ceremonies involving sake and the exchange of haisen, showing how important sake is in Japan, which is also why haidai stands, haisen basins, and all the other items associated with sake-drinking came to be used.