The short answer: hands separate first, then join at a tempo slower than both hands' solo tempos
Get each hand secure playing its part on its own, then join them at a tempo slower than both hands' separate comfortable tempos — slower than the faster hand's solo pace, and slower than the slower hand's solo pace too, not an average of the two and not simply the pace of whichever hand is weaker. Coordinating two independent hands is a distinct skill from playing either one well, and it needs its own runway: dropping the tempo below what either hand alone could already manage gives you the spare attention to actually listen to both parts landing together, rather than just surviving the passage. Only once that combined version is genuinely clean at the slower tempo does it make sense to bring the speed back up.
Why hands together is a new skill, not just two familiar ones added up
This is exactly the next stage once "hands separate first" has actually been done — not a way to shortcut past it. It is tempting to assume that once each hand can play its part well alone, playing them together is just a matter of doing both at the same time, but coordinating two independent parts is a genuinely different skill from playing either one, not a simple sum of two skills you already have. Each hand alone only has to track its own notes and rhythm; playing hands together means simultaneously tracking two independent streams of information while keeping both honest, and it is common for a hand that was completely secure alone to suddenly stumble the moment the other hand joins in — not because it forgot its part, but because attention that used to go entirely to one hand now has to split. Treating hands-together practice as beneath serious attention, on the reasoning that both parts are already known, is one of the most common reasons this stage takes far longer than beginners expect.
Joining a few beats at a time before the whole phrase
Join both hands together for a small chunk — a single beat, a single bar, sometimes even a single chord change — rather than attempting the entire phrase together on the first try. Work a small unit until it is solid, then extend outward, rather than trying to absorb the whole passage together in one go and hoping the coordination sorts itself out along the way. Pick the smallest chunk where both hands actually meet — often just the first beat of a bar, or the exact moment a left-hand chord changes under a right-hand melody note — get that single moment reliably clean, then extend to two beats, then the full bar, then the phrase. It feels slow at first, deliberately so; a shaky whole phrase rushed together rehearses the shakiness as much as it rehearses the music.
Contrary motion vs similar motion
Contrary motion — the two hands moving in opposite directions, one climbing as the other descends — is often noticeably easier for beginners to coordinate than similar or parallel motion, where both hands move the same direction at the same time. The reason is mechanical: in contrary motion the hands use mirror fingering, so both thumbs land together and there is one finger pattern to track instead of two. This is a general tendency worth knowing about, not a fixed law of piano technique — plenty of real passages move in similar motion and simply need to be practised as what they are — but if a passage feels unusually hard to coordinate, it is worth checking whether it happens to be moving in similar motion, since that alone can explain some of the extra difficulty.
The tell-tale mistake: one hand quietly borrowing the other's timing
One specific mistake is common enough to name directly: one hand quietly borrowing the other's timing instead of holding its own independent rhythm. It usually happens to whichever hand is playing the less secure or less familiar part — under the pressure of coordinating, that weaker hand's rhythm subtly bends to match the stronger hand's, rather than both hands actually locking to a shared pulse. The result can sound almost right, which is exactly what makes it easy to miss without listening for it specifically. This is a hard thing to hear in your own playing, since it is your own sense of time doing the borrowing — it is exactly the kind of subtle timing slip a teacher catches immediately from across the room in an early keyboard or piano lesson, which can take a self-taught player weeks to notice alone.
When to bring the tempo back up
Only raise the tempo once the hands-together version is clean at the current one: if you cannot play the passage correctly, hands together, three times in a row at today's tempo, it is not yet time to speed up, however slow that tempo already feels. Nudge the tempo up in small steps rather than jumping toward your target speed, and if a step causes the coordination to fall apart again, that is useful information, not failure — drop back down, consolidate, and try the increase again from there. The tempo you eventually want to reach was never in question; how carefully you get there, without carrying the same coordination problem along at a faster speed, is what actually determines how solid the passage ends up being.
Keep going
- Finger Numbers, Hand Shape and Posture: Your First Week at the Keyboard — the hands-separate habits this post assumes are already in place before joining hands.
- A 20-Minute Practice Routine You'll Actually Stick To — a repeatable twenty-minute structure that survives a bad day, on any instrument.