Flagged Revisions installed. Unapproved pages display a Red unchecked notice under the title. Trolls attack here by creating and archiving pages with offensive content. To verify an archived page, check the original URL. Questions about administration? Contact User talk:Abd. Limited privacy on this site, see CFC:Limited privacy

Sudoku/Puzzles/Extreme/Nakimoto Extreme/1

From CFC
Jump to: navigation, search
Nakimoto 2019 Extreme 1

This puzzle is visible (the first in the book) in the Amazon preview of J.B. Nakimoto, Puzzle Book Extreme Level: Diabolically Difficult Puzzles for Advanced Solvers (2019)

Figure 1. SBN r1c5={45}

SBN coloring

  • light orange cell: seed cell for chaining
  • green: first chain. Convention: lowest digit or Gordonian cell number.
light green: alternate cell candidate within green chain.
  • red: alternate chain.
light red: alternate cell candidate within red chain.
  • purple: mutual elimination.
  • light purple cell: contradiction (multiple in region or empty in color)
  • light blue cell: mutual resolution (as only colored candidate in cell)


First coloring[edit]

After cleanup, Simultaneous Bivalue Nishio process was begun with r1c5={45} (Figure 1, right). The 4 chain extended well, coming to a contradiction, all candidates were eliminated in r6c9, so r1c5=5.

Second coloring[edit]

Figure 2. SBN r6c7={56}

After cleanup, again SBN on r6c7={56} (Figure 2, left). The 5 chain comes to a contradiction, so r6c7=6.

Third coloring[edit]

Figure 3. SBN r1c9={16}

After cleanup, BSN again on r1c9={16} (Figure 3, right). As the coloring became complex, the shown eliminations were implemented and coloring was continued.

Figure 4. continuation of 3rd coloring

The 6 chain completed the puzzle (Figure 4, below left). The 1 chain was finally contradicted, the mutual resolution of r5c8=9 eliminates a 1 chain colored candidate, therefore the 1 chain contradicts itself. [r9c8=4]

Click for solution..