This is a very rare marked Japanese Groove Float.

The mark is WP #170 Asahi 旭.  It's been stamped three times on the seal.  I'm thinking that the sealing iron may have had the Asahi mark in a triangular configuration.

One unusual aspect of this float is that it's more of an oval shape rather than the typical round shape you see in glass balls.  In this float, it's taller than it is wide.

I think this is an excellent example of this type of float and it even has its original net.