ShotoNoob
Master Black Belt
\There is a great deal of debate where Hwang Kee actually got his Karate from. He claims from books. But he also trained and learned "chinese forms" from a Korean who trained under Toyama Sensei (and this Korean was trading CMA art for OMA with Toyama, and both were under the Imperial bootheel)
But I have my reasons to think G. Yamaguichi taught Hwang Kee a bit in Manchuria while they were there at the same time.
Hwang Kee says Yamaguichi is a close personal friend of his.
Well having witnessed some Tang Soo Do first person... I would say the blending of TMA other than Shotokan was a certain plus. TKD too, can be more fluid and not so physical & overly-aggressive as some of the Japanese karates. We saw so in that excellent TKD-kickboxer YT vid someone here posted....a while ago.
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EDIT: The TSD School {dojang} I recently visited claims northern Shaolin kung fu in it's style as a secondary influence...