Identify this brand of belt?

[MarkC]

My original Black Belt, which I got in 1987, is 2" wide, the label sewn into the end is balck with a gold circle which contains inside it a red symbol that looks like the Mitsubishi emblem, the 3 diamonds connected , I've heard the symbol represents a leaf or something. The diamond shapes contain three letters arranged like this: T
N I

I never really thought about it all these years, but suddenly I'm curious. Anybody recognize the company?

 

[MarkC]

.T
N I
That's more like it.