If u are playing a song on piano in the key of CMaj, for example. Are u only allowed to use these chords?
Cmaj, Dmin, Emin, Fmaj, Gmaj, Amin, Bdiminshed.
BEcause i read that these are the scale chords for the key of CMaj, so if im playing a Cmaj song, am i only allowed to play these chords?
thanx

If it's tonal music...then I suppose yes....

But that's all I know. I expect someone else will shed more light.

You can play any chords you like. It just so happens that many of the chords based around the scale of C major are the ones most used e.g F major and G major.

In saying that however there are some chords used more often e.g. D major to modulate to G major would be found a lot more often than say E minor or B diminished.

Look at any collection of pop songs and you will find chords that are not wholly derived from the notes of the scale of the key in which you are playing.

Those are the triads for C Maj but you could add sevenths to them, especially to the V (G maj) which unsettles it so that it sounds more final when you play C Maj after it (this is a very common perfect cadence). You can use those chords but you don't necassarily have to stick to them.

If you decided that a certain note not in the scale of C Maj (for example A flat) sounded good then you could try modulating to a different key (C min) or just play a chord that fits.

If you wanted to modulate, try finding a note of chord that is in both scales (C Maj and then the scale you want to modulate to).

thanx very much.

thanx very much.

Sometimes you can also use chords which seem totally alien - e.g. a C major chord followed by an Ab major chord - because they both have a C in the chord, and sound particularly good if you keep the C at the top of both chords. Or sometimes the flattened 7th - e.g. again in C major, a Bb chord followed by a C major chord. Or you can string together an Ab chord, Bb chord and a C chord. It all depends what style music you're playing - these work well in more contemporary popular styles, but if it's a more classical style you're writing in then keeping to the traditional I ii iii IV V vi vii is better. (Having said that an Ab chord in C major - particularly with an F sharp is some sort of Neopolitan 6th chord I seem to remember - so it's not just used in pop!)

I think the neapolitan 6th is the flat-IIb (b as in 1st inversion).

Traditional -
Flat-IIa (#3) is sometimes used but mainly for modulation.

Yes, it's great if you want to insert tonic minor chords in a major piece.

I - flat-IIb(#3) - Va - flatVIa(#3)* - iv a(b3)* - V7a - Ia

* lifted out of the tonic minor.

It does lots of other modulation like C to Ab:

In C :-----Ia - - - - - - -flatIIb#3 - flatVIc(#3) -
In Ab:----(IIIa#3)- - - -IVb - - - - Ic - - - - - - - V7a - - Ia



ps in case of query I put in the #3s as well as capital romans to affirm this is a major chord.