It is a zabuton designed for a gift in celebration of kiju (one’s 77th birthday)

The kanji for happiness ‘喜’ written in the cursive style looks like the three kanjis ‘七十七’(meaning 77). For this reason, the custom of celebrating one’s 77th birthday has prevailed after the Edo period.

In some cases, the honoree is supposed to wear purple garments such as a haori or a sleeveless vest and a bouffant cap, and sit on a purple zabuton in celebration of kiju.