I remember buying it because I thought, "Where did they get this?" and it was unusual. This isn't a standard two-blade white persimmon plane; both blades have a ruler face on the left side. So, both are used for processing the right side of a marking line. https://daiku-dougu.jp/nicyoushirakaki.html It's also listed here. I learned the name for the first time. For you, who, like me, has a passion for detail.