22 నిమిషంలో పూర్తి చేశాను. మంచి పజిల్ కృతజ్ఞతలు.

I must say this puzzle kept me working for a while, but in the end, a pleasure to solve without notations.

It is a trick one. Being somewhat pessimistic I could solve it notation free, I attempted it making limited and strategic use of candidates. That got me so far after which I found it really hard to find restrictions, so have given up on it.

This was one of the most difficult for a while. 17 mins. no pencil marks.

Not too bad with a UR (54 = row 5 column 4): 98, 47, 62, 25 (hidden single, owing to partitioning of box 5), 74, 94, 44, 46, 41, 13, 51, 52, 53, 42 (hidden single, owing to hidden pairs in column 3), 65, 45, 69, 49, 48, 39, 32 (UR, boxes 1 and 4), 27, 71, 63, 61, 23, 21, 72, 92, 76, 79, 78, 17, 26, 28, 18, 37, 75, 77, 19, 36, 85, 93, 83, 96, 86, 91, 81, 99, 89, 38, 14, 15, 84, 34. And not too bad without: 92 instead of 32 (naked single), 76, 79, 37, 36, 84, 15, 27, 32, 71, 63, 61, 23, 21, 72, 89, 99, 81, 91, 86, 96, 83, 93, 85, 75, 19, 18, 38, 14, 24, 17, 28, 34, 78, 77.

NF