Kumi Biwa Bokuto

This is a KumiBiwa wooden sword.
38 years ago, when I was preparing for a dan promotion test, the dojo master at the time gave it to me, saying, Use this.
I passed the dan promotion test with this wooden sword.
The nameplate says KumiBiwa, but after researching Biwa wood, I found that it is not something an ordinary kendo practitioner can use.
Upon closer inspection, Biwa wood is difficult to obtain nowadays, and it is said that camellia wood, which has the same material properties, is sometimes used.
I researched the difference between Biwa and camellia wood, but as an amateur, I couldn't tell.
The dojo master has also passed away, so I cannot ask him.
Even if it is camellia wood, it would still command a certain price.
I hope it is Biwa wood, but the price has been set considering the possibility that it might be camellia wood.
1. Weight = Specific gravity is almost the same for Biwa and camellia.
2. The grain and color are characteristic of Biwa.
3. The attached tsuba is plastic, which does not match the material.
4. There is an inscription on the pommel: Made by Miyakonojo Horinouchi Noboru Seisakusho (closed in 219).
5. No warp.
6. There are some marks from a magic marker on the lower part of the tsuba.

The more I research, the less I understand.
Thank you for your consideration.

Although not visible at first glance, upon closer inspection, there are marks from practice.

Thank you for viewing.