Ise Katateuchi

Several people have suggested Muramasa School. This is a koto Katateuchi, "One-handed  Fighting Sword" of the period. The Sugata and Hada is very much like a 1st Generation Muramasa I once owned.
Shinogi-Tsukuri Katateuchi with wide Chu-Kissaki.
Running Itame Hada stands strongly. There are two lines of Utsuri running up from the Moto area.
The Hamon is a Muramasa school, Nioi Midare Notare Ba with some Hako shapes. The Yakiba appears to weaken in the Kissaki area.
Nagasa: 20"

 $650 - write:
In American Shira-Saya
Otherwise Ubu Nakago
Inscribed  "Sa"