i aswell found this:
The Nakano Shoten in Tokyo was a well-known provider of koshirae (sword fittings) and other sword accessories, especially during the time of World War II. It was owned by Mr. Nakano and also had branches in China.
Unfortunately, there is no precise information available about the founding or closing dates of Nakano Shoten. Some reports mention that similar shops still exist today as tourist attractions, but without specific details about their current status.
If you own a sword stamped by Nakano Shoten, it is likely a military Gunto from the World War II era, outfitted by this company. These swords were often made for officers and soldiers and are now highly sought after by collectors.
For more accurate dating and authentication of your sword, it is recommended to consult an expert in Japanese swords or a specialized auction house. They can help determine the age and origin of your katana precisely.
looks interesting for me