As Mark mentions there was quite the Japanese influence in Thailand. Should you get the chance check out the Grand Palace in Bangkok as you enter there is another section that will cost you few extra baht to enter, but well worth the investment. It house much of the Royal jewelry, arms and insignia. It was there through and interview with a guard that I learned about the different royal ranks and who could what (enamel, copper, silver, gold, jewels) on their accouterments. Apparently there were court rules that governed all of this - never did find a copy.
But you've got to stop by the armory - dha galore - and surprisingly keris also. But the one part that stuck in mind and has to do with what Mark is talking about here was a small sign near, what I thought was, a katana. Mentioned that in 1660 (I think) a Japanese merchant was elevated to the rank of Chao Praya (or one those ranks), the highest achieved by any foreigner after he raised 3000 troops (from within Thailand) to fight for the king in one of the wars.
That along with the fact that the Japanese used to trade blades for Thai rayskin, the Prince's sword is a Thai katana and I'm thinking that qualifies as significant Japanese influence
