Hellraiser Cube

The Hellraiser cube is an evil puzzle. At first glance, it looks like opposite faces look the same but there are subtle differences.

I took the precaution of photographing each face, so that I could ensure that I solved to look exactly as it looked when I first removed it from the packaging.

When solving this puzzle, I use the layer method. I solve the pieces as normal, check them against the photographs and swap the ones that are not exactly correct to ensure I return the puzzle to the exact same configuration as when I first removed from the packaging, the lament configuration.

Not I puzzle I play with a lot, but it is a nice one to have in the collection.

Katsuhiko Okamoto's Latch Cube

Latch Cube

The Latch Cube, invented by Katsuhiko Okamoto, is a variant of a normal 3x3x3 cube where some pieces can only be turned in one direction. Edges with black arrows can only be turned anticlockwise and edges with white arrows can only be turned clockwise. A face that has both black and white arrows is locked, thus bandaging that face.

Turning, unsurprisingly, was not the best but this was improved with some lubrication.

The colour scheme is non-standard. I suspect it was altered to facilitate the contrast of the black and white arrows against the colours. This may upset some people, but it is not a speed solve puzzle, so it should not be an issue.

The mechanism that hinders the cube is simple. The catches can be seen in the photo below and affect the F- and B-faces.

Solution

This is not an easy puzzle to solve. The latching prevents some algorithms from working while others must be adapted such that, say, R' might have to replaced with R3.

Scrambling the cube is not trivial: it is all too easy to lock up a face. 

Step 1: Cross

I think it is slightly easier to solve the arrowed pieces first, but I am not sure. Even so, it is not straight forward. Getting this far feels like a minor achievement.

 

Step 2: E-Layer Edges

Getting these four edge pieces into place is far from trivial. Black and white arrows cause bandaging everywhere and edge pieces will have to be moved out of the way to free up faces. If possible, I try to rotate the edges on the final layer but this is not always feasible.

Step 3: Final Layer Edges

If the pieces are rotated correctly, then this is relatively straight forward. If not, it is trickier, especially if there are black and white arrows on the final layer face.

Once the puzzle is in this state, while still not straightforward, it does become a bit easier. The direction of the arrows on each face are solved. While the puzzle is still not trivial, at least there is now some order. Figuring out modified algorithms for the corners is not as difficult as the edges. 

Step 5: Permutate the Corners

This is not as difficult as it looks, provided you can consistently perform a three-quarter turn instead of a quarter turn against the direction of the arrows without getting confused.

Step 6: Orientate the Corners

Like the previous step, this is not as difficult as it appears. Using the beginner method algorithm works if you can substitute three-quarter turns where needed.

This is a challenging, at times frustrating but satisfying puzzle to solve.