This is a very nice full mounted daito with an NBTHK Hozon certificate attributing it to Echizen Seki (a school dating from late Koto into Shinto times).
Echizen province is in present day Fukui prefecture on the western coast of Japan. The Echizen Seki school was one of the two principal schools of sword smithing in Echizen, the other being the Yasutsugu who were originally from Omi province. The Echizen Seki were created by smiths moving from seki to Echizen. and were particularly active from 1658 -1680.
This is a nice long blade with a low choji-midare hamon. Black tsuka wrap with very high quality Nio (temple guardian) menuki. The menuki has an NBTHK Hozon certificate. Iron jingo tsuba and shakudo dragon fuchigashira. Black lacquer scabbard. copper habaki.
Hamon: Gunome-choji some pointed togari-gunome, In nie-deki
Jitetsu: itame with mokume mix. blade has muneyaki
Boshi: ko-maru
Nakago : 21.1 cm
Nagasa: 70. 0 cm
Moto-haba : 2.9 cm
saki-haba: 2.1 cm
moto-kasane: 0.6mm
Saki-kasane: 0.5mm
Kissaki: 3.2cm