PNSSHOGUN

May be among this Mon: https://irohakamon.com/kamon/shikaku.html

Thank you, as you can see the casting quality is lacking and detail on the sides has been completely abandoned. Likely late 1944 or 1945 production.

Hello Connor, this appears to be a genuine Japanese sword. The sword dates to the 1700's and the maker is Ason Yasuyo, whether the signature is authentic is another matter. The fittings are traditional Samurai style that have been modified for the war. If you know about the history of how your grandfather took the sword in Burma, I would type it all out and keep it with the sword as a nice bit of family history.

Some closer pictures of the Tsuka may help, the casting quality fell right off by 1944-45.

Welcome Connor, given it was acquired in Burma I would hazard a guess it will be in Military mountings. If you post it in the section you can kill two birds with one stone: https://www.militaria.co.za/nmb/forum/45-military-swords-of-Japan/

If memory serves me right these were purposefully cut at that angle to allow a slight tension to avoid falling out. It would also allow easier removal as the handles sit further away from the Fuchi. You will find this detail on many good quality Koshirae with Kozuka.

Is the blade made in Bizen Den?

Mon in this case refers to the Akihide trained group of smiths.

At the end of the day it's a real Japanese sword with decent looking Kai Gunto Koshirae, but if you look closer the cracks start to show. There are a number of dealers from Japan offering these sorts of pieces, the prices are certainly low but all sorts of skulduggery may have been applied to them. The polish is rather poor and typical for rush jobs that photograph well but obscure details The blade appears tired and has Ware (flaws) showing all over It may be a symptom of the polish but the Hamon appears rather weak Looking closer at the fittings, they may have been re-gilt

You're leaping to some pretty tenuous conclusions without demonstrating basic knowledge about Japanese swords.

Many of the swords listed have some pretty significant issues, with the prices reflecting that. The mounts aren't too bad on this but the blade is a mess.

Likely one of the many Tosho from the Akihide Mon.

Looked to be classic Bizen Yokoyama Sukesada.

Were these photos taken after a polish?

Rather unique, at a guess something thrown together for field service during the Meiji period.