you might have better look in r/whatisthisthing

It's a Chinese military dagger. An officer's dagger. These are usually called "KMT daggers" or "Nationalist daggers", and you should be able to find similar examples using those as search terms (note that many of those similar examples will be modern fakes).

Some had genuine tortoiseshell (covered) grips, and others had plastic imitation tortoiseshell grips, and others had different non-tortoiseshell-pattern grips.

One of the main routes for these to come into Western hands during WW2 was Burma, where Chinese units were fighting alongside Western units. As something distinctive and different from the usual Western gear, while being compact and easy to carry, these were desirable souvenirs to trade for.