The upper of a long Tachi, - this Daimyo chose for his personal sword. 
Billowing Soshu, fine Konie O-Midare Ba Hamon. Kinsiji, starkly defined Sunahashi brushes Hakikake of top quality Ara-Nie and arcing Inazuma leaps from the Hamon in the lower. A true and rare quality. Wet Mura Ji-Nie on strong, runnng Hada.
The Shumei lacquer is genuine, the attribution is correct. 
NBTHK Tokubetsu Hozon

            This sword is a high quality masterwork