Logic Masters Deutschland e.V.

In this continuation of the Cavern Crawl series, explore the caverns with the help of lockout lines.

Rules:

Normal Sudoku rules apply: the digits 1-9 must appear in every row, column, and 3x3 box. In this puzzle, cages are used to distinguish the 3x3 boxes.

Thermometer: There is a single 2-cell thermometer (key) in the grid. Digits along this thermometer must increase from the bulb end. In the online solving tool, the thermometer will appear normally.

Lockout Lines: The light blue lines are lockout lines. The endpoints of each line (marked by diamonds) must have a difference of at least 4, and the digits on the line may not be between nor equal to the endpoints. Digits may repeat on the lines if allowed by other rules.

Caverns: Horizontally and vertically adjacent digits must have a difference of 3 or less except when separated by a “wall” (thick purple line). Adjacent digits separated by a wall may have any difference. A 3x3 example is provided below. Note: Be mindful of the edges, as some can be easy to overlook or can be mistaken for box edges. I experimented with a variety of designs and found purple walls to be best for this particular puzzle.

Solve online using Penpa+. Use "Sudoku" and the rightmost "B" for answer check.

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