SudokuSolver Forum

There are four difficulties to choose from.
All four puzzles have the same solution.

A) Novice
B) Apprentice (mainstream edition).
C) Master (35 Intersections, 3 Naked Pairs, 4 Naked Triplets, 3 Naked Quads, 1 Hidden Pair, 1 Y-Wing in g3, 2 XY-Chains up to 5 links: one in g1 and one in g3). Select to view GRID numbers.
D) Chief Wizard. Solvable using logic only? JSudoku needs 1 Recursively Solve, which makes 8 guesses and traverses 4232 nodes.



Regular Samurai #15A (Novice)

Rating based on required solving techniques:  Moderate

000900205009030700080100600003018000007000040200000063000000000400020070001609000
003100000050000208000800006000007000001000620000514800000000000000030002008002059
000308000070200000000000008000060002703090005800030000000940000000000000100000000
040005000090000000000000100000502390020008000600010000100000800005760003400000050
000030007000080000000070108000700000000200604900050000002000000005300790600094350



Regular Samurai #15B (Apprentice)

Rating based on required solving techniques:  Barely Hard

000900205009030700080100600003018000007000040200000063000000000400020000001609000
003100000050000208010800006000007000001000620000514800000080000000030002000002059
000308000000200000000000000000060032703090005800030000000940000000000000000000000
000005000090000000000000000000502390020008000600010000100000800005760013400000050
000030007000080000000070108000700000000200604900050000002000000005300790600094350



Regular Samurai #15C (Master)

Rating based on required solving techniques:  Ultra Hard

000900205009030700080100600003018000007000040200000063000000000400020000001609000
003100000050000208010800006000007000001000620000514800000000000000030002000002059
000308000000200000000000000000060032703090005800030000000940000000000000000000000
000005000090000000000000000000502390020008000600010000100000800005760013400000050
000030007000080000000070108000700000000200604900050000002000000005300790600094350



Regular Samurai #15D (Chief Wizard)

Rating based on required solving techniques:  Hellish Nightmare   Solvable using logic only?

000900205009030700080100600003018000007000040200000063000000000400020000001609000
003100000050000208010800006000007000001000620000514800000000000000030002000002059
000308000000200000000000000000060032003090005800030000000940000000000000000000000
000005000090000000000000000000502390020008000600010000100000800005760013400000050
000030007000080000000070108000700000000200604900050000002000000005300790600094350

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Børge
I can confirm that Chief Wizard #15D is solvable using logic. It does require regional forcing chains, their application in Grid 1 assists JSudoku on solving the puzzle.

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I have 81 brain cells left, I think.

You are absolutely right.

After having JSudoku solve as far as possible, I found the following forcing chain in g1:
(r5c5 = 5)
=> (r1c5 = 6) => (r1c3 = 4)
=> (r5c2 = 1) => (r5c1 = 9) => (r5c9 = 2) => (r4c8 = 5) => (r9c8 = 2) => (r9c7 = 5) => (r9c5 = 4) => (r3c5 = 7)
=> (r1c6 = ?) => (r5c5 = 6)

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That move alone isn't enough to crack it.

My first move instead is this Kraken house move. (which you should appreciate being Norwegian)


JSudoku can now advance to this position for Grid 1.



Another Kraken (based on cell r8c4)



Now JSudoku can finish it

It is always best to go for moves that affect the overlap region.

_________________
I have 81 brain cells left, I think.

I knew that at the time of posting but forgot to mention it.


I absolutely agree, but I could not find such a move.


Two excellent Kraken.
The second one is especially impressive.

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