Index Lookup Sudoku

🧭 Index Lookup is a mind-bending variant created by Logic Wiz, expanding on the classic 1-5-9 mechanic. In this version, marked cells act as GPS Pointers- the digit inside tells you exactly where to find that cell’s own row or column number.

↔ Horizontal Lookup (The Column Pointer)

When a cell in Column X has horizontal arrows, the digit inside acts as a Column Address.

• The Rule: The digit tells you which column contains the number X in that row.
• Example: Look at cell B3 (Row B, Column 3). It contains a 6.
  • This means the digit 3 must be placed in Column 6 of that row.
  • Check the image: You can see the green thumbs-up at (B, 6) where the 3 is located!

↕ Vertical Lookup (The Row Pointer)

When a cell in Row Y has vertical arrows, the digit inside acts as a Row Address.

• The Rule: The digit tells you which row contains the number Y in that column.
• Example: Look at cell D7 (Row 4/D, Column 7). It contains a 7.
  • This means the digit 4 (representing Row D) must be placed in Row 7 of that column.
  • Check the image: The digit 4 is correctly placed at (G, 7).

✥ Combined Lookup (The Dual Pointer)

If a cell has both sets of arrows, the digit inside (Z) points to both a Row and a Column address simultaneously.

• Example: Look at cell F2 (Row 6, Column 2). It contains a 9.
  • Horizontal: The digit 2 (the column) must go in Column 9 of that row.
  • Vertical: The digit 6 (the row) must go in Row 9 of that column.
  • Check the image: You’ll find the 2 at (F, 9) and the 6 at (I, 2)!

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🧠 The Golden Rule

Digits in marked cells point to the location of that cell’s own identity.

💡 Logic Wiz Tip: Not every Index Lookup cell on the board is marked with a symbol! Sometimes you must use standard Sudoku logic to deduce where these hidden pointers are.