Matcha or Maccha

Do you spell “matcha” or “maccha"?

The other day, I was asked which one is correct from the perspective of Japanese language. I replied, “I guess either is fine." 

As long as I know, the spelling of “matcha” is more common while the other one is not often seen here in Japan. However, I just learned that a new tearoom opened in Kyoto. It is named “Maccha House.”  ------  OK, I have to research now. 

Japanese language has a double [long] consonant known as sokuon that English doesn’t. In order to represent sokuon in English, there is a basic rule that the consonant has to be doubled. (based on Hepburn System) For example; 
kite ( "come") – /kite/
kitte ( "postage stamp") – /kitːe/ or /kitte/
asari ( "clams") – /asaɽi/
 assari ( "easily") – /asːaɽi/ or /assaɽi/                       (Reference: Wikipedia)

If you follow this rule, “maccha” seems to be correct, but there is an exception. In case of the sound of “cha”, ”chi”, “chu”, “che” and “cho”, the letter of “t” has to be added before them. It means “cha” has to be “tcha” to represent a double [long] consonant.

I know it’s confusing and not clear. Sorry! The point is, according to my research, “matcha (ma-t-cha)” is considered grammatically correct. Let me take back my reply, saying "Either is fine". Again, this is just from my research. I will not bear full responsibility even if it is not 100% right, but ......allow me to say, "I'll take matcha."

Instant Powder for Matcha Ice cream