Cast Vortex

One of the most difficult Hanayama Cast puzzles is "Cast Vortex". Personally, I find it to be in Top 3 of the most difficult from the series so far.
My first encounter with this puzzle was when one roommate of mine got it for his birthday. At that point I did not have any puzzles in my collection (i.e. my collection had not yet been started). It was rated at difficulty 5 (out of 6) by Hanayama and I gave it some tries. At one point it seemed that the three pieces could not move to any direction and I thought the puzzle was stuck. But my roommate managed to solve it and with few more tries he was able to do it very fast. Then, I gave it no more tries, but I wanted to get some of these puzzles for me as well.
Some years later, when I bought this puzzle, I still found it very tricky. There are several places where one can have difficulties in moving the pieces, there are few dead-ends, although they are not so tough. If one is cautious, they can realize in time that these are dead-ends and can go back to try something else.
So, it took me a dozen of tries to remember the path and to solve the puzzle relatively fast. But still, sometimes I am not able to do it immediately. The puzzle is very tight, the solution is very precise and the pieces are very stubborn. Maybe that is why when Hanayama made re-evaluation of their puzzles (I cannot remember when exactly, but it was after 2010), they promoted "Cast Vortex" to level 6. And I agree with them. It is very difficult to apply the solution even after knowing it.

I also cannot deny that the design of this puzzle is perfect. It was very important to make the pieces precise, to put the obstacles on the correct places and to make the features fit properly to only those parts of the solution, where they are really needed. What I mean is that every one of the three pieces has two protrusions and one hollow on its surface. For each piece these are situated on different parts of it. These both help in finding the solution and torturing when one reaches a dead-end. And one common thing about all three pieces is that they look like the number 6 (but not closed 6 - there is a small opening on the pieces which the number 6 does not have at that place). This is the reason why I call "Cast Vortex" a devil puzzle - having three 6-like pieces and being tough enough, it should really stand for a devilish puzzle.
My ratings for "Cast Vortex" are the following:
Idea: 6
Implementation: 6
Experience: 6
Difficulty: 6
Overall: 6
This puzzle was not only hard to solve, but hard to rate as well. I think the rating is higher than I expected I would give it, but considering everything, I cannot give less in any category than this. Maybe in time, when I do my own re-evaluation of the puzzles, I will update this review, but for now this is how I rate "Cast Vortex".