I quickly whipped up a 10×10 easy Masyu for Puzzle 1. The puzzle looked so boring that I decided to inject a bit more life into it. I aimed for a complete set of pentomino pieces in the givens but the grid was too big for uniqueness. I had to add more pieces and a few circles to get a valid puzzle.
A straight-forward solve to start the first 100m of the track
Puzzle 2: Yajilin
I picked one puzzle from the last Nikoli Hurdles to feature here and it was a Yajilin. An error posed a problem for early solvers when I had a 3 mistyped as a 2. Funnily, Prasanna who ran into the error; correctly assumed I had a typo and just tweaked the puzzle himself!
He continued the track without me even fixing it in time. About the solving, I thought it was a nice Yajilin with clue symmetry. Grandmaster Puzzles recommend using unclued grey boxes in Yajilins in which I can’t say I agree to. Those remind me of “cheater black squares” in American crossword puzzles. They’re there to make the author’s life easier while preserving the puzzle, which I don’t think is a pretty thing to do.
A fairly difficult solve as solver Ivan Koswara vaguely remembered: “I think I recall the Yajilin being extremely tough or something.”
Full PDF of Nikoli Hurdles 2: here