Question of 6/8 time signature and beats?

Music in 6/8 can be ambiguous: sometimes it is 3/8 + 3/8 (2 beats in a bar) and at other times it is 2/8 + 2/8 + 2/8 (3 beats in a bar). Composers in the renaissance and baroque used this a lot, what is called a hemiola, when the normal 3/8 + 3/8 switches to a bar of 2/8 + 2/8 + 2/8 just before a cadence. A good modern example is Leonard Bernstein's America in Werst Side Story: "I'd like to|live in A|mer-ic-a.

A 6/8 can be slow or fast. A slow 6/8 will be counted as six eighth notes. A fast 6/8 is usually counted just as the two large beats to make it easier.

the rule you gave is only accurate for "simple" meters, like 2/4 3/4 4/4 2/2/ 3/8 4/16 etc...

6/8 is a "compound" meter.

meaning several measures of 3/8 stuck together.

the rule would apply to the little measures of 3/8 inside it...

but for a compound meter, you zoom out, and count those little meters as beats themselves.

so 6/8 is two beats and the beat is a dotted quarter (because 3 8th notes = dotted quarter).

it would be more convenient if we could put 2 on the top and a dotted quarter on the bottom, but there's no denominator that equals a dotted quarter. some composers have literally drawn a dotted quarter on the bottom of the time sig!

so instead:

think of 6/8 as 2 x 3/8

think of 9/8 as 3 x 3/8

think of 12/8 as 4 x 3/8

(and think of 6/4 as 2 x 3/4 etc...)

In 6/8 there are six eighth notes in measure and the eight note counts as one beat...in 3/4 there are three beats in a measure and the quarter note gets the beat...you can count 6/8 in 2 if you choose because it has a swing feel to it, but in 8 years of band I never saw anyone count 3/4 in two...

It IS 6 beats, and each is an eighth note. There are many example of this - like the famous Bach Siciliano. BUT - when the tempo get faster and/or more flowing, it is convenient to count two triplet - ONE two three FOUR five six - just as ONE . . TWO . . This s a conventional understanding among musicians, for centuries.