So I'm an intermediate-ish keyboard player who's been playing very irregularly for the past three years, all self taught. I have recently started taking it more seriously and found a group of people I play with regularly. We have a bass player, a drummer, a guitarist, a violin player and a vocalist.

When we don't play covers, we often jam.

During jam sessions, I would usually lead with my own chord progressions and the others would follow me. But some other times, (say) the guitarist would come up with a theme, then we'd have to follow him. When that happens, I'm a bit lost : I have no problem finding the key/scale I can use to solo over and make something that sounds decent, but I really don't know what to do with my left hand : I don't know what chords to play, and playing octaves of the root note doesn't sound good. So I would just stay on the root chord for the whole thing because I really struggle to find "on the fly" a chord progression that matches the current groove. I am also not fluent at all coming up with left hand bass patterns and I feel like it would clash with the bassist's playing if I tried.

What am I supposed to do in this situation ? How can I practice using my left hand more creatively during jam sessions (when I'm not leading) ?

Thanks for the help, and apologies if this has been answered before, but I haven't been able to find what I'm looking for using the search bar.

  • 1) Are you jamming in any particular style? 2) Also, can you tell by ear if a chord is major or minor?
    – Aaron
    Aug 21, 2021 at 4:20
  • Are you playing some form of free jazz, where the chord progression is not defined in advance? Aug 21, 2021 at 6:10
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    You don't want to hear this, but if you don't sense what's happening harmony-wise i.e. what chords are being played, then you don't know what you're doing even with single note lines. Whatever you play always changes the total harmony (and rhythm) in some way. Then the only option is to play "safe" neutral pentatonics or something. You might be able to fake something by playing quartal chords in the key, but it'll get boring pretty quickly. And still if there are chromatic alterations like Am - Bm in the key of Am, if you can't hear the harmony, you'll ruin it if you play an F note. Aug 21, 2021 at 6:43
  • @StratosFair "The guitarist would come up with a theme ... I don't know what chords to play." To clarify: do you mean that the guitarist is playing chords and you're having trouble identifying them? Or that they're playing more of a rhythmic or melodic "riff" and you're having trouble choosing chords that suit it well? That becomes a question about how to harmonize a melody. Aug 21, 2021 at 16:45
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    Usually when a group improvises on some idea, that idea is a melody (or a phrase, or a riff, or whatever) together with some chords that place that first bit in a harmonic context. Players who can improvise cold from just a melody are probably pretty well developed. If your guitar player wants to introduce a riff for everyone to jam along with, they should come up with some chords, too (and they might already be hearing something in their heads). Or, when someone drops a riff on the group, the whole group should take a minute to figure out some good chords to tie things together.
    – user39614
    Aug 21, 2021 at 17:13

3 Answers 3


To play well in this sort of situation needs a heck of a lot of knowledge and experience. I suspect you find solace in using penatonic notes - as they omit a couple of 'iffy' notes that will clash in a lot of situations. Using those two notes needs to be done very carefully, as they're what get called 'avoid notes' - for obvious reasons.

It's not going to be very successful to continue with the way you're going - as you're aware. When you're the leader, you have your chord sequence mapped out - maybe in your head, maybe on paper. The rest of the band has to keep in sync with what you play, so they must go through the process you're missing, otherwise nothing would gel. Ask them what that process involves, and there will be some clues to help you.

In the initial stages, it won't go amiss to actually stop and write down what someone's sequence is. It may be a 4, 8 or 12 bar long sequence, which repeats - like a lot of music does. At least then, you'll have reference points to home in on.

You need to be aware of which chords are likely to work together - I, IV and V are frequently used, so when you listen to a sequence, and have established I, start writing out that sequence. Every time you hear I, write it, put a dash for all other chords. Keeping the bars in 4 to a line will reflect what often happens in a song anyway. Then listen for V, and write that down where some of the dashes are, as you hear that V. And so on.

If you're not aware of the 'chord families', it's time for some learning! Along with the 3 major harmonies, there could often be 3 minor ones - ii, iii and vi. Get to the point where you could write out a sequence on the fly, as you listen to it. Songs off the radio are a good source. Eventually, you won't need the writing bit - you'll map it all out mentally, and play along the second time in harmony with the rest of the band.

ALL THIS - to reach your question! As without the above skills, it ain't goin' nowhere!

Having reached this level of musicality, left hand can play all sorts - those being in tune with what else the others are playing - a very good thing. That could be stabs (use 3 and 7 from the chord being played - no need for full chords). It could be a 'wash' of sustained chords, which again will now complement what the others play. It could be unison with the bassist - if either of you is adept enough to pick up on what the other is playing. It could be nothing. When the guitarist is strumming, there's no need to even take your left hand out of your pocket.

There's a starter for you, but the skills at the beginning need honing first. Good luck.

  • Many thanks for this well written answer which gives me a rather decent guideline on how to practice to achieve my goal ! I'll just a wait a little bit more to see if some other useful discussion arises before accepting it. Aug 21, 2021 at 16:59

Edit. If the guitarist and bassist are playing only single-note riffs or power chord riffs, you still need to know what the notes and power chords are. If you don't, how can you reason about what the total combination of notes is?

Anyway, I figured out something you can do with your left hand: operate the Leslie speed switch and drawbars. Assuming you play a Hammond style organ. If you play a synth, you can operate its various tone controls.

The combination of all notes played by all players together create a total harmony. If you don't know what you're doing, and if you play random things, you are making random changes to the total harmony. It's hit and miss, sometimes you find a note that sounds nice, so you better remember that note. ;) But if you really don't know the chords, it's a difficult situation where you don't have much leeway.

I tried to think of various different possible roles that a pianist might take and what the left and right hand do in those scenarios. But in every case, the pianist has to know what the chords are and how his left and right hand are changing or amplifying the chords.

  • Left hand: single bass note comping + Right hand: chordal lines --> Have to know the chords.
  • Left hand: long chords, Right hand: melodic lines. --> Have to know the chords.
  • Left hand: short chord stabs, Right hand: melodic lines. --> Have to know the chords.
  • Left and right hand, both playing chords, either together or alternating, for example LH Fm7 + RH Cm7 = wide Fm11 --> Have to know the chords
  • Left and right hand together play melodic riffs or arpeggiating chord lines --> Have to know the chords
  • Left and right hand play in an interval, for example a sixth --> it adds to the backing chords/notes anyway --> Have to know the chords
  • Right hand playing single notes only --> it adds to the backing chords/notes anyway --> Have to know the chords

You also need to know if there are chromatic alterations baked in the chords If the guitarist plays the chords Am7 - D9 - F9 - E9, you have to hear that there's an F# in the D9, an Eb in the F9, and a G# and F# in the E9. No way around it. Left or right hand, separately or together.

If you don't know the chords, how can you operate. If the guitarist plays e.g. an F, F7 or F9, you can add a B natural note (or even a whole G major triad) over it, creating a nice Lydian'ish feeling. But if you don't know what the guitarist plays, how can you do this, how can you reason about what's happening? If all you know is the key, how do you even explain to yourself what you did?

If your instrument produces clearly distinguishable pitches, you need to know what the chords are, and what your notes make them be. This applies to your right hand as well. It sucks to jam with a player who doesn't know what the chords are and how his notes relate to the chords, regardless of instrument. What if it was a bassist? It would be a ridiculous idea to bring a bass player to a jam who has no idea what chords should be played, I guess you understand that. Many guitarists try to develop techniques and playing styles which conceal the fact that they don't know what's happening in the harmony and where the notes are on the fretboard. So they play pentatonics, licks, or just random stuff from a scale. Particularly the random approach is bad.

If you're going to jam, you have to know the chords, otherwise you suck, individually and as a group. This applies to your violinist, guitarist and bassist just as well. The way HOW you get to know the chords can vary. If they need to be written down, then so be it, as long as the players know the chords. If someone introduces chords that another person can't figure out, creating a harmonic mine field, the other person has to either let the "chord leader" know, find at least one safe note (by chance), or just cease to play anything. It's about communication and getting to know the other players. If you put together a group of random players, there is a settling-in period when everybody gets familiar with each other and adapts their playing to what can and cannot be done in the group.

  • Having, on occasions, played with people who just 'widdle', I agree totally that ignorance of the harmonies that make up the piece is an absolute no-no. There's no coherence, no structure and no point. In fact, an absolute no-no-no... I usually ended up having no clue where in the piece any of us were, so often stopped playing. What else to do?
    – Tim
    Aug 21, 2021 at 16:42
  • Thank you very much for writing this detailed answer which clearly shows that I am merely at the beginning of my musical journey* (deleted previously incomplete comment). I have to say however that I am not quite sure what I should take away from this : does your reply imply that, as long as my ear is not as developed as what you describe I can't jam with other people ? When we do these jams and the guitarist comes up with a riff we play over, he usually doesn't really know what the underlying chords are, and it just doesn't feel right to stop and write down everything we do anyway. Aug 21, 2021 at 16:45
  • So the guitarist is playing something like lines of power chords, i.e. perfect fifths? What does the bass player do with that stuff, double the root note of each power chord in unison with the guitar? In that case, a piano or keyboard player can often largely make up a chord progression, as long as it makes sense together with the guitar+bass riffs. Even in this case you need to know what the power chords in the riffs are. If you don't know, then you don't know what the total harmony becomes. The violinist has the same problem! Aug 21, 2021 at 17:01
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    I have to offer a dissenting opinion: "If a thing is worth doing, it is worth doing poorly." Learning "what to play" takes an awful lot of discovering what not to play. If the whole group is having fun making a spontaneous noise, hey, why stop. But if you're getting frustrated or want to grow more, you might do well to have more structure. You said you often play covers, and when you don't you jam: maybe you need something in between; use the familiar chord changes of a cover and improvise over them or make your own altered versions (turn a power ballad into a samba, etc.) Aug 21, 2021 at 17:06

You need to know what the chords are, if your improvisations are to have any meaning.

But, to answer the main question, whether you understand the chords or whether you’re just getting away with pentatonic scales, when playing with a bass and guitar the best thing to do with your left hand is often - nothing. Keyboard CAN cover bass, chords and melody. You’ve got other people covering two of them.

Plenty of videos out there of pianists playing with guitar bass and drums. Here's one to get started with.

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