Sake Flask (pair), 1500s. The grape design painted on these wine flasks reflects the popularity of grapes and wine during the Muromachi period. Japanese Zen clerics enjoyed grapes during this period, and Ichu Tsuzo (1349-1429) and Saiin Shunsho (1358-1422) wrote poems about their appreciation for other artists? grape ink paintings. On these wine flasks, the vividly brushed leaves and bunches of grapes suggest that the artisan referred to a particular grape painting.