Undulating hamon (zigzag).

The beginning of designed pattern may be ko-gunome or kataochi-gunome that started in Bizen province in 13th century. We find a small amount of such pattern in the hamon of Kageyasu blades (brother of Mitsutada). He might be one of the first smiths who put some design onto hamon intentionally. Two generations later, the kataochi-gunome was sophisticated as a well ordered pattern by Kagemitsu.