This is a 240mm (9 sun) Ryoba saw made by Sadagoro Nakaya. A blacksmith praised as first-rate by Nagakatsu, a master of saw sharpening. The straightening is also, as expected, first-rate. Sadagoro is a disciple of the 5th generation Inosuke. The younger brother of the 2nd generation Inosuke is the famous Sadayasu Shibuki. The explanation will be long, so please search for more information. I also use this saw on site. A hard-to-find saw. Rust has developed due to long-term storage. It should not affect use. Also, it may be possible to remove some of the rust with a cutter or eraser. Therefore, I am offering it at a low price. Thank you.