It is a zabuton designed for a gift in celebration of one’s 70th birthday. The purple colored one is common just like a kiju-zabuton or a sanju-zabuton.

The word ‘koki’ is derived from the poem of ‘Kyokko’ written by Du Fu, a Chinese poet of the Tang dynasty. Since the poem has the passages meaning that it has always been unusual for men to live to seventy, the ancient Japanese came to use the word ‘koki’ to celebrate one’s 70th birthday.