x1 is a musical comma of size x2, a small difference resulting from the different intervallic approaches x3 and x4, in tuning system x5.
x1 and x2 are the same as for "togyku'e", while x5 corresponds to the x3 of "togyku'e". The x3 and x4 of this word correspond to different constructions that "should" result in the same pitch, but don't (e.g. four 3/2 fifths vs. one 5/4 major third, for the syntonic comma of 81/80). This word is not to be used for a "microtone" in general - that is "cmato'aku'e". See also: togyku'e, cmato'aku'e.