Solutions to Nikoli Hurdles – 5/5

600-700m: Mochikoro
I wanted one not-so-known variant and Mochikoro came to mind. In fact, I listed a lot more of rare Nikoli types hoping to include a few of them. I settled for less when I thought the idea might deter away newcomers. If there’s another set of Nikoli Hurdles, do expect less familiar types.

nhurdsol7

For this puzzle, I strived for symmetry for almost an hour but settled on the odd 1 in the top right corner. When you have a reasonably hard puzzle, adding their symmetrical counterpart botches up its difficulty. If someone understands the basics of Mochikoro, then this puzzle shouldn’t be too hard because no difficult steps are needed.

700-800m: Country Road
This is also a first for me. I wanted to come up with a new break-in before drawing up a grid. I played around with the two crosses that each housed a 5. The top-left U pentomino was the starting point. We know that the path must enter and exit two of the four arms of the cross. The 4 in the top-left U pentomino meant that the left arm has to be used.
nhurdsol8a

Now look at how the crosses lie on each other. Either the bottom or the right arm of the first cross will be left unused, which means the left arm of the second cross has to be used. The path exits the second cross through the bottom arm and the top of the puzzle falls easily. After this, the rest is elementary.
nhurdsol8b

When constructing I put the pieces into the grid and added their symmetrical counterparts as I go. The regions are symmetrical but you can’t use the same deduction for each side. In all, I thought this was a good and interesting puzzle.
nhurdsol8c

That’s it for the puzzles in Nikoli Hurdles. Thank you everyone for your kind comments, feedbacks and overall participation. I’m thinking about Nikoli Hurdles 2 but not in the near future as there are other things I’d like to get done. Please look forward to other experiments I will be trying out somewhere over the rainbow.

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2 responses

  1. For this puzzle, I started at the bottom right-hand corner. R10C10 can’t contain a loop section without breaking the rules. From there on, one can already get a large amount of the puzzle done (assuming one knows a few Country Road solving procedures).

    One should also notice that since any arm of the cross that is used must be FULLY used, squares like R4C3, which border two arms, can’t enter the crosses. Those two observations are pretty much enough to solve the puzzle. Hooray for alternate solving paths.

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