kjp

So apparently I’m a bit of a nerd. I’m writing all this up because I’m likely to forget bits of it (in particular the spinning of the centre pieces).

Anyhow, for my birthday I got a sudoku rubiks cube. It’s a rubiks cube, but instead of 6 colours, each face has the digits 1 to 9. Each face has to have all of the digits 1 to 9 all facing the same way.

Before I started, I took photos of it, in case I couldn’t get it out, but these weren’t needed. It’s a harder puzzle than a standard rubiks cube. With a rubiks cube, you know where each piece has to go (each face has a different colour). With the sudoku rubiks cube, you don’t know (initially, at least) where each of the pieces has to go. And (with my rubiks cube at least), there’s no restriction on the orientation of the centre pieces (I think some there are smiley faces?).

Anyhow, after I’d figured out the solution to my puzzle, I had to figure out how to spin centre pieces.

So here are some of the moves required:

Some definitions:
A = Face A – face towards you
B = Face B – face on the right of A
C = Face C – face above A and B

+ = rotate clockwise 90° when looking on A, B or C
- = rotate anti-clockwise 90° when looking on A, B or C
++ = rotate 180° when looking on A, B or C

Ao = Opposite side to Face A – face away from you
Bo = Opposite side to Face B – face on the left of A
Co = Opposite side to Face C – face on the bottom of A, B, Ao and Bo.

Am = Middle section between A and Ao
Bm = Middle section between B and Bo
Cm = Middle section between C and Co

Corner piece – piece with 3 sides
Side piece – piece with 2 sides
Centre – centre of a face – 1 side.

Some moves
These are only some of the moves required (at the latter stages of solving it).

Spin three corner pieces
This spins three corners on C, with the corner in the bottom left fixed. The side pieces on C are affected.
B+ C+ B- C+ B+ C++ B- C++

Spin a single centre piece 180°
This spins the centre piece of C by 180°.
Do Spin three corner pieces (above) three times

Move 3 side pieces
This moves the side pieces between A and Co, A and C and C and Ao. The piece between A and Co goes to between C and Ao, other two pieces shuffle down.
Bm- Co++ Bm- Co++ Bm++

In the process, this spins A and C centres by 180°.

Spin two adjacent centres by 180°
This spins the centres of A and C by 180°.
3 x Move 3 side pieces (easy – basically shuffling the three side pieces, but A and C centres get rotated by 3 x 180° = 180°.

Alternatively: (same principle, just slightly quicker):
Bm- Co++ Bm- Co++ Bm+ Co++ Bm- Co++ Bm+ Co++ Bm- Co++ Bm++

Spin two adjacent centres by 90°
This spins the centre of C by 90° (anti-clockwise), and also spins the centre of B by 90° (clockwise).
Bm- Cm+ Bm+ C+ Bm- Cm- Bm+ C-

Solution to my Sudoku Rubik’s cube
The solution took a while to get.

The basic process was to work on the corners: the orientation of the numbers on the corners tells you which corners can be adjacent to each other. It’s possible to gradually figure out which corners go where. Several pieces on the side of the top and bottom can be placed (due to their orientations), and then the centres of the surfaces can be determined, and then finally the remaining side pieces.

137a = 71 read together (left to right)
137b = 13 read together (left to right)

TOP FACE
137a – 3; 89 – 8; 137b – 7
24 - 2; 1 – 1; 79 - 9
245 – 5; 36 - 6; 469 – 4

BOTTOM FACE
159 – 1; 25 – 5; 258 – 2
49 – 4; 6 – 6; 33 – 3
467 – 7; 28 – 8; 689 – 9

SIDE FACE # 1
245 – 4; 36 – 3; 469 – 6
37 – 7; 5 – 5; 12 – 1
159 – 9; 25 – 2; 258 – 8

SIDE FACE # 2
469 – 9; 79 – 7; 137b – 1
12 – 2; 4 – 4; 68 – 8
258 – 5; 33 – 3; 689 – 6

SIDE FACE #3
137b – 3; 89 – 9; 137a – 7
68 – 6; 1 – 1; 58 - 5
689 – 8; 28 – 2; 467 – 4

SIDE FACE #4
137a – 1; 24 – 4; 245 – 2
58 – 8; 7 – 7; 37 – 3
467 – 6; 49 – 9; 159 – 5