SOONER OR LATER, if you play music, you'll have to play a keyboard. It may be a piano, an organ, a synthesizer, or a sampler. It may be your first instrument, or your second, or your ninth. You may be using it to play music, write music, or record music. What is beyond doubt is that you will need to have some kind of keyboard playing ability at your disposal. Not a stunning virtuosity, just the knowledge and the dexterity necessary to get by, in whatever situation you fnd yourself having to run your fingers over a set of black and white keys.

And whichever of the above statements is true for your own circumstances, you'll find this series of features useful for developing just such a basic keyboard-playing ability. The aim is simply to produce an organised view of harmony on the keyboard, based on a sound grasp of musical detail.

To start with, all you need to cope with is using letter names to describe the note content of any musical idea. Later, that will have to expand into some reasonable view of musical notation, but this is not essential to get off the ground. Diagram C shows two octaves of a keyboard going from C to C, with the white notes labelled by letter name.

You'll notice that there are only seven letter names used (A-G), and if you play the three G, your ear should tell you that these are the same note repeated at different pitches. Play the notes in Diagram D.

This probably makes a familiar sound, because it's what we call a "major scale", the basis of a whole tradition of western music. More than that, it should be the basis for the development of your harmonic thinking for some time to come, so it makes sense to find out what makes it work.

If you look at the notes again, you'll see that some are separated by a "black" note (C-D, D-E, F-G, G-A, A-B) and two sets of notes are adjacent (E-F, B-C). These last two sets represent the smallest interval in western music on a fixed tuned instrument, and are called semitones; the others are called tones. So remember: any two adjacent notes are a semitone apart, while two notes with one note between them are a tone apart.

Going back to the C major scale shown earlier, it's now possible to see the spacing in Diagram E, with T indicating a tone and S a semitone.

Now repeat that starting on a G. (Look back to the diagram of the keyboard if you can't remember the note names.) You should arrive at Diagram F.

Why the F#, and how do you play it? Go back to the earlier picture of the piano keyboard - we labelled white notes only. To find sharps (#) and flats (b), you simply go up a semitone for a sharp, down a semitone for a flat. So F# appears because we wanted to preserve the sound of the major sale; and to do that we had to produce a sequence of tone, semitone, tone, tone, tone, semitone. We have now produced the same major sale, but at a different pitch. Try Diagram G, which starts on F.

Why the Bb? Exactly the same as before - just to satisfy the familiar sound of the major sale, and this time, you find Bb one semitone below B. Incidentally, a "scale" is a sequence of notes organised by step, all of which have a different letter name.

It's possible to go on and produce major scales starting on any of the 12 semitones, and this is a routine you should go through, at the keyboard and on paper, writing out the letter names and, if you're feeling adventurous, the notation too. What you should finish up with is Diagram H (the scales are arranged in a particular order which will become clearer later in the series).

Some of these are fairly remote, and you'll not come across them very often, but you might as well give yourself the full picture. The most important thing to remember is that these are not separate musical problems, but one idea reproduced at different pitches. All you need to remember is "tone tone semitone tone tone tone semitone", or "TTS TTTS", and starting from any note you will produce a major scale.

This information is fundamental to the construction of basic chords, which is what we'll tackle (head on, I promise) next time around.