I just got a Type 1 rifle from the Navy Vet who brought it back from Japan after WWII. Can anyone tell me anything about the writing on the sling or the wooden tag on it?

Thanks,

Chief

here is the rest of it;

here is the tag;

Chief

the back of the tag;

Chief

Here are a couple more pictures.
What is the best way to start cleaning it?
(It has not been cleaned or fired in 63 years!)

Chief

another;

Chief

Thanks for looking.

Chief

Chief, they are numbers in first photo. Can't read other kanji. Numbers don't seem to match rifles serial number (rarely do) so they're likely rack numbers. If you ever decide to sell or seperate I'd be interested in sling if it's still pliable.