Japanese cloth map, military?

[tthen]

Found this map a while back, I'm not sure what it's for, or if it's even Japanese. It's approximately 15" x 15" and feels like it's made of cotton. once again sorry for bad photos. Hope something can be found out.

Thank you

Tom

[tthen]

1

[Eric Queen]

Japan for sure. The Seto Inland Sea. 瀬戸内海  

 

https://en.wikipedia.org/wiki/Seto_Inland_Sea

 

Doesn't seem to be military related.