blade length 57.0cm, curvature 2.1cm, thickness at the base 7mm, width 2.9cm
This is a wakizashi from koto period. It is difficult to see the age, but may be 15th century or older. It is a simple sword without any tricky appearances, but interesting to see the activities in the blade.
Steel is clear color, and it has some rough layer in some part. Probably the steel is not forged very carefully.
Hamon is made of small particles. The active hamon pattern is not well designed. Utsuri, Yubashiri, and some other activities also appear irregularly.
Hamon sketch (oshigata)
Of course, it is impossible to take all the activities by sketch. One of the interesting things is the hamon in kissaki. It is quite different between obverse side and reverse side. Such hamon can be found only on old koto blades.
Tang: It is hammering finish, and originally no signature.
This is a typical sword what is used by single hand. It can be specially called "Katate-uchi", or some people say "this is The Uchi-gatana". The terms are the shape like short tachi around 60cm blade length and short tang. Such swords are found from the very beginning of koto period to 15th century.
In total studying of this sword, the tang looks very old, but the the curvature and the hamon with some Gunome pattern suggests it 14th century - 15th century. The appearances look like the swords those are attributed to Hoju, Mokusa or so. Anyway attribution is not very important. The point of this sword is, this simple weapon has many interesting activities in the steel those are not intentionaly designed. When you study those activities, you can come into the entrance of Nirvana.
The polishing is the classical style (Sashikomi style). It is done recently. So we can study the activities very well.