This is by far one of the coolest puzzles I have ever seen. Even after you solve it, it makes an awesome desk toy; it's immensely satisfying to simply play with and move the gear around. While it isn't super difficult to solve this by accident after moving the gear around randomly for a long time, coming up with an actual solution (by which I mean, a full movement algorithm, with which you could reliably move any tooth of the gear into any of the six faces of the cube in any desired orientation) will take quite a bit of thought. For someone new to the puzzle scene, this is probably the best place to start. Like all Hanayama's puzzles, it's built rock-solid and will never bend or break unless you're really trying to, so it'll basically last forever. And it only has two pieces (which are pretty big), so it'll also be pretty tough to loose one of the parts. If you're seeking a serious challenge, this is decidedly NOT going to be it. This is just a casual puzzle that's pretty to look at and fun to play with. I honestly couldn't recommend this enough for someone who's either new to puzzles, or just wants an awesome desk toy. For people who have experience solving these types of puzzles, this one is admittedly going to be pretty easy to solve. HOWEVER... finding the "optimal" solution to this puzzle (i.e., the solution which removes the gear in the fewest possible moves, starting from the position with the two slotted teeth of the gear resting in the face with those two grooves) is indeed extremely challenging, even for advanced puzzlers. So, if you've finished solving this puzzle and are looking for an extra challenge to keep you occupied, see if you can reason out the most efficient solution! Although I have never seen Hanayama's official solution to this puzzle, I can tell you with confidence that the 'minimum' number of steps needed to solve this puzzle is 10. (Or alternately, 17 steps, if you choose to count 'twisting the gear' as a step.) If your solution involves more than 10 movements of the gear, it is not the optimal one. **Note: I found this solution computationally, so I'm fairly convinced that it's the correct one. (Writing a computational model of this puzzle was an awfully fun challenge in and of itself... I invite you to try it!) However, if you've found a solution that involves fewer than 10 steps, please let me know! Or, if you're interested in seeing my solution, just ask and I'll send it to you.**
