Hello, I've named this wakizashi "testamentary blade." The nakago (handguard) is signed and dated, as is the shirasaya (handguard). Ama Hide, 8th month of Bunsei 7.
Suishinshi Masa Hide passed away on the 27th day of the 9th month of Bunsei 8.
Here is a modern translation of the engraved text:
The principle of sword making is clear, and I am not afraid to measure myself against the swordsmiths of old, but that doesn't mean I despise them. This art simply consists of bringing the iron to a perfect state by eliminating impurities through forging, and there's no point in obsessing over the temper line (the hamon). There is no doubt that the harmony of Yin and Yang makes the blade pure and sharp, and difficult to break. I've attached another photo found online of his signature, Ama Hide, placed in the same spot and truncated by the mekugi ana (handguard).
It would be interesting to learn why he made this (these) blade(s)..