Ko-kinko ymagane cast tsuba of oval form with chiseled diaper pattern of double head waves on both sides and a rabbit cast and carved with its eye inlaid in yellow metal (gold or brass) on the face. Fukurin which holds together the sandwiched layers of metal (sanmai) is about 2.7 mm wide. Possibly, early Mino (ko-Mino) school. Size: 66.6 x 59.9 x 4.0 mm. Some connoisseurs believe that this kind of tsuba was in mass production at the time. Small animal believed to be a fox, however some attribute it to a long-tailed rabbit or a squirrel. I am leaning towards the rabbit. Similar example is found at Robert E. Haynes Catalog №3, April 9-11, 1982 on page 11, under № 15: “Rare design in style of Sanmai (three layers) / Wasei work. With yamagane core and heavy rim cover. The web plates are carved with double head Goto style waves and the face has a fox. The web plates were riveted at the seppadai.  See Lot 4, page 8. Ca. 1350. Ht. 6.6 cm, th. 3 mm” [underscore mine]. Quality of photo is so poor that I decided not to provide it here. The only difference betwen my tsuba and his is that his has a square hole on the right shoulder of the seppa-dai. Early Muromachi (if we follow Robert it is even Nanbokucho, 1337-1392) or Momoyama period. The Momoyama attribution is mostly based on a fact that “waves and rabbit” motif became most popular in Momoyama times. Mokkōgata tsuba of similar design in this collection - see TSU-0282.