Signed Naval sword with surrender tag

[phil reid]

Hello Gents , after a bit of gentle tapping and light cursing have removed hilt off this WW2 naval sword, tang has a bit of rust but not sure whether to gently remove, there's light chalk numbers i don't want to interfere with or is it best to remove? Worst runs on the spine. Is it clear enough to read? also came with surrender tag . Your thoughts and any help appreciated.

 Hope photos are ok

 Regards 

Phil in Perth

[kyushukairu]

Hello Phil,

The nakago itself is signed 'made by ?? Masakane, a resident of Noshu Seki' (濃州関住??正兼作)　
I'm not too sure about the middle two characters, as they are quite indistinct, but it's most likely a surname. Perhaps you can provide a better photo of them?
 

The wooden tag is quite odd, and I'm not convinced it is a surrender tag. 
The characters  at the top (左舷) mean 'port' (as a nautical term). Below that is the name of a person.
The surname is Sasaki (佐々木). The first name 平 is quite generic and can be read as any of the following: Osamu, Taka, Toshi, Hitoshi, Masaru, Yoshi.