How to Solve a Clock - Step-by-Step Course

Before you start

Pick up your Clock - the best way to learn is to repeat every move on a real puzzle. You can rotate the animations in this course: drag the Clock with your finger or mouse to see the other side and the wheels on the edges.

What a Clock is made of

• 18 dials (clocks) - 9 on each side, in a 3 by 3 grid. Each hand points to a full hour, from 1 to 12.
• 4 pins - buttons between the dials. A pin that is up on one side is down on the other - it is the same peg. In this course a pin that is up (pushed out towards you) is yellow, a pin that is down is dark.
• 4 wheels in the corners - you use them to turn the dials. Each wheel is connected to the corner dial above it.

A solved Clock has all 18 hands at 12. There are no colours - only the hours matter. In this course one side is dark and the other is light; your Clock may have different colours, it makes no difference. Always hold it so that 12 on the dials is at the top.

How it works

Around each pin there are 4 dials - a 2 by 2 square. A wheel turns all the dials in the squares around the pins that are up (on the side where the pins are up). With one pin up, 4 dials turn; two pins next to each other - 6 dials (two rows or two columns); three pins - 8 dials, all except one corner; four - the whole side.

Important: turn the wheel next to a pin that is up. A wheel next to a pin that is down turns the dials on the other side - this is the most common reason why a solved side suddenly falls apart.

The corner dials are shared. A corner dial on the front and the corner dial on the back are the same gear seen from two sides. When the hand on the front moves clockwise, the one on the back moves the other way. Thanks to this you never set the corners of the first side at all - they solve themselves when you solve the corners of the second side.

The solving plan

1. First side: cross - the centre and 4 edges at 12. Four moves following one rule and one move with all pins.
2. Flip - the second side towards you.
3. Second side: cross - the same as on the first side.
4. Second side: corners - four moves following the second rule and one move with all pins. Clock solved.

There are no algorithms here - in every step you keep turning until two hands show the same hour. The whole solve is usually 12-14 moves.

1Pins, wheels and notation

You do not need notation to solve the Clock, but it is useful for the animations, the cheat sheet and competition scrambles. A move is always: set the pins, then turn a wheel next to a pin that is up.

• Pins up: UR, DR, DL, UL - one pin (U = up, D = down, L = left, R = right); U, D, L, R - the two pins on that side; ALL - all of them; lowercase ur, dr, dl, ul - all except that one. The remaining pins are down.
• Turn: the number of hours and the direction. + = clockwise, - = anticlockwise, always looking at the side in front of you. UR3+ = push up only the UR pin and turn the wheel 3 hours clockwise.
• y2 - flip the Clock so the other side faces you, like turning a page in a book: a rotation around the vertical axis, 12 stays at the top. The pins reverse by themselves.

Click a move to see it on the Clock. The yellow outline shows the dials that turn:

Also look at what happens to the other side: after UR3+ rotate the animation or click y2 above. Only one dial changed on the back - the corner one, the same gear as the UR corner on the front - and it shows 9, because seen from the back the turn goes the other way.

2First side: cross

Goal: on the side in front of you the centre and 4 edges (top, bottom, left, right) show 12. The corners do not matter.

You can start on any side - the easiest is the one facing you after the scramble (in the animations it is the light side). The centre turns with every move (it is part of all four squares), and an edge turns only when one of the two pins next to it is up. The whole method follows from this:

Rule 1: to match an edge, push up the two pins on the opposite side and turn until the centre shows the same as that edge.

The pins on the opposite side do not move that edge, so as you turn, the centre “catches up” with it. The edges that already match turn together with the centre - so nothing gets messed up. Turn whichever way is shorter.

1. Right edge: L pins (both left) up, turn until centre = right edge.
2. Left edge: R pins (both right), until centre = left edge. The right edge moves together with the centre.
3. Bottom edge: U pins (both top), until centre = bottom edge.
4. Top edge: D pins (both bottom), until centre = top edge. Now the whole cross shows the same hour.
5. To 12: all pins up (ALL) and turn until the cross shows 12.

The order of the edges can be anything, as long as the pins are always on the side opposite the edge you are matching. It is worth sticking to one order, though - then your hands will remember the moves on their own.

3Second side: cross

Goal: flip the Clock and set the centre and 4 edges on the second side to the same hour (not to 12 yet).

Flip the Clock (y2): the first side is now at the back. Its cross must not move any more - and it will not move if you only turn the wheel next to a pin that is up. A wheel next to a pin that is up turns only the dials on the side in front of you (and the corners, which are shared).

You make the cross on the second side exactly the same way as on the first - rule 1, the same four steps. Do not do the ALL move at the end yet: the cross stays at one, any hour, because it will soon be turning together with the corners.

Rotate the animation after the step is done: the cross on the first side is still at 12. Only the corners changed - on both sides, because they are the same dials.

4Second side: corners

Goal: all 9 dials in front of you at 12. Then the whole Clock is solved.

The edges already show the same hour as the centre. Now it is time for the corners - and the second rule, similar to the first:

Rule 2: to match a corner, push up all pins except the one next to that corner and, using a wheel next to a pin that is up, turn until the centre shows the same as that corner.

With three pins up, everything turns except one corner: the whole cross and the other three corners. So the corners that already matched move together with the cross and still match. Do this with each corner in turn, and finally ALL - all pins up and turn until everything shows 12.

Why did the first side solve itself? Its cross has been at 12 since the start of step 3 and nothing moved it, and its corners are the same dials as the corners of the second side: when they show 12 on the front, they show 12 on the back too.

Cheat sheet: the whole method

Always turn the wheel next to a pin that is up, and whichever way is shorter.

Printable cheat sheet (PDF)

Solve it yourself

The simulator works like a real Clock: click a pin to push it down or up, and turn a wheel - by dragging along its edge (or over the corner dial) or with the buttons below. A wheel next to a pin that is down turns the other side, just like in reality. Choose a step to practise only that step.

Common problems

• After flipping, the first side fell apart. The wheel was turned next to a pin that was down - then the dials on the other side turn. On the second side only turn the wheel next to a pin pushed up towards you. If the cross on the first side is already broken, flip the Clock and make it again (rule 1).
• An edge that matched no longer matches. The pins were on the wrong side: when matching an edge, both must be on the opposite side and all the others down. Check that no pin is stuck halfway.
• A corner will not match the centre. In step 4 the pin next to that corner must be down, and you turn the wheel next to one of the other three. The wheel at that corner itself (with its pin down) turns the corner and the other side.
• A hand stops between hours. In models without magnets the dials can stop halfway. Gently nudge it with the wheel to the nearest full hour before you start comparing.
• A wheel turns stiffly or locks up. Usually one of the pins is only pushed in halfway. Push the pins all the way in one direction or the other. Do not force it - Clock gears are easy to damage.
• I turned the wrong way. No problem - keep turning until the hands match. In this method all that matters is that two dials show the same hour, not which way you turned.

What next?

The method from this course solves the Clock in 12-14 moves, and after a few days of practice - in under a minute. When you want to solve faster:

• Count instead of turning “until it fits”. Look at two dials, count the difference in hours and turn the wheel by exactly that much straight away - without watching the hands as you turn.
• Turn two wheels at once. When you turn one wheel next to a pin that is up and another next to a pin that is down, you make a move on the front and on the back at the same time. This is what fast methods are based on, e.g. 7-simul: a few moves done with two wheels simultaneously, with the hours calculated in your head before the first move.
• Clock at competitions. Clock is one of the WCA events. Competition scrambles are written the same way as in this course, e.g. UR3- DR2+ … ALL5- y2 U4- … ALL3+ - you can apply them on your own Clock, and in the simulator “Scramble” gives a scramble in the same format.

If you enjoyed the Clock, try the puzzles from our other courses - you will find all of them below.