Jap Type 30 Bayonet- Trainer

[Midmichigun]

Greetings!
Just like on my Jap Rifle Trainer thread... I have a few questions...
I got a Type 30 trainer bayonet recently. This is not "sharp", and is in pretty good shape. It has a full quillion and ok wood. I have noticed that the metal finishing isn't very good... in fact you could call the quality rather "rough". It doesn't have any makers marks... Here are some photos:


Of importance... and interest... is the following mark:

The above photo, looks like a Naval "anchor" on the wood hilt. Look carefully, worst case scenario, is that I circle it for "ya all". What is this??