Didn't say they did. But your statement that "Japan wasn't involved in the fighting" in WW I is mistaken.
The link you provided say’s japan ‘’seized’’ German ports in the Far East. “Siezing’’ something is different than fighting for it. I’m not unaware of japans involvment in WW1 but the person I was posting to made the assertion that German and Japanese graves were bomber in WW1 and WW2. The former is incorrect.