Japanese naval shell?

I have inherited a shell case that my great grandfather brought home from WW2. He was in the Merchant Marines.
The case is 28 inches tall, mouth has a dent, but is roughly 5 inches and the case head is 6 3/4 inch. I have been googling on and off for a while and can not identify it. Any help would be appreciated. If I can identify what it is and what gun it was used in I was thinking about putting it on display at the USS Lexington which is just down the road in Corpus Christi.

Hi Ron, welcome to the forum.

Looks like a case for the 12 cm Type 10 gun. Please, can you post a picture of the headstamp?

Regards,

Fede

The thing that is strange is the fact that there are numbers and letters with the Japanese markings.

Wow, that’s a rare one. It’s normal for them to be stamped with numbers and kanji (Japanese characters).

If you part with this shell I might be interested.