The Edo Ishido School was active from the early 17th Century until the Hattori(cessation of sword forging) in Meiji Period. The most famous smith line was the Korekazu. By the end of the 19th century, sword making resumed and the son of the last master resumed the line which exists until this day. The blade is evidently osuriage having all of the original signature(if it had one)cut-off. A very nice example for your collection.