Eyes to the heavens, fingers to the keyboard. Andy Honeybone twists the digits of your left hand into ever increasing brilliance.

TWO'S AN INTERVAL three's a chord — notes, that is. Our left-hand style survey continues by cleaning up on single note exercises and moving on to two-note shapes.

Worn weary by last month's rhythmic explosion, you'll no doubt be intrigued by a brief description of locked-hands style. Instead of the left-hand supplying a bass line, it moves up the keyboard to double the top note of a four part chord played with the right.

The style was invented by Lionel Hampton's pianist/arranger Milt Buckner, popularised by George Shearing, and was intended to mimic close-voiced, big-band horn sections, so it's a useful technique for the synthesist. The only example that I can dredge up that you may have heard is Weather Report's version of the Ellington classic 'Rocking In Rhythm', hut it's hardly typical.

Try the following: play a C6 with the right-hand (E, G, A, C) and double the top note (C) at the lower octave with the left. Now, sticking to the white notes, move the entire shape up and down the keyboard (hence the term locked-hands). For added zip, slip in brief semitone appoggiaturas (grace notes) before the left-hand note and break up the blocks with faster passages simply in octaves. As they say in all those jazz tutor books, 'transpose to all keys and memorise'. That's when it gets complicated as there are about 400 chords to learn to cover every mode in every key.

Moving back down a couple of octaves, we come to walking basses. Historically, promoters were quick to realise that a piano could simultaneously play the bass line and so cut the payroll. Roots and fifths generally fall on the even beats of the bar with practically anything fitting in between. Rhythmic skips and chromatic anticipation add interest; accenting the second and fourth beat contributes extra swing.

The most important aspect of the walking bass is its unrelenting presence. Play any note that comes into your head but never falter. It's the bass that keeps the tempo in a band so keep going at all costs. Walking basses appear in many 1950s rock 'n' roll songs as well as in more up-market offerings like 'Walk Between The Raindrops' from Donald Fagen's "Nightfly" solo.

Popular two note left-hand accompaniments result from opposite ends of the musical spectrum: the early blues and boogie-woogie styles were designed to inject rhythm while establishing a solid root; the be-bop shell system, conversely, was a minimalist approach to allow the horn-like right-hand statements to predominate.

The Meade Lux Lewis favourite 'Honky Tonk Train Blues' features the left-hand alternating between doubly stated fifths and sixths in a swing dotted quaver pattern. OK, you've guessed it. I mean the Status Quo rhythm. Another variation begins in the same way, but after the repeated fifth it breaks into single notes to sound the minor and major thirds.

I recently chanced upon some footage of that Bruce Hornsby and immediately noticed his large left-hand being put to use playing tenths. My hands aren't big enough to stretch that far but I have heard that, like most things, practising helps no end. The style is very useful for solo work as the combination of root and third clearly states your harmonic intentions. Teddy Wilson (Benny Goodman's pianist/arranger) was a tenths man, but he also included other intervals such as the seventh.

It's been said that although Charlie Parker was a great harmonic innovator, he homogenised the playing styles of several generations and so destroyed the natural character of instruments other than his own. The 'let's play like Parker on the piano' league was headed by Bud Powell who invented a left-hand harmonic scheme based on thirds and sevenths. The note-pairs were never played rhythmically but were stated, often as minims, to underpin the frantic right-hand soloing.

The minor seventh interval gets used most as it can imply a dominant seventh chord, a half-diminished chord, or a minor seventh chord. The major seventh is often used to convey the tonic major chord. The major third sounds weak and, although it may be used for the major or dominant chord type, it is most frequently used in more animated II-V sequences where it alternates with the minor seventh. The style is effective on those electronic keyboards where you can otherwise drown the right-hand, with an overdone left. Vibe or marimba timbres are particularly good as the 'shells' approximate multi-mallet technique.

And to finish, not so much a style as an imitation of a guitar. Cameo's 'Wordup' has a bass line of fifths for each of its three main chords. The chords move down and back up in tones starting as suspensions resolving to majors. Later, the first chord changes to minor just at the point when you think you've got the hang of it.