This is the third in a series of Sudokaches exploring different sudoku variant rules. "Thermo" sudoku puzzles are descended from sudoku and relational puzzles, and designed to provide a simplified and more visually interesting presentation of inequality concepts compared to other puzzles that primarily used greater than/less than symbols. This name was first given to the style in the 2009 book Mutant Sudoku by sudoku champions Thomas Snyder and Wei-Hwa Huang.[1]
Normal Sudoku rules apply. Also, the digits along a thermometer must increase, starting from the bulb end.
Some hints for those who haven't seen this variant before, highlight text to read:
- Thermometers may have gaps but digits may not repeat; for example, a 4-cell thermometer may contain the digits 2, 5, 6, and 8 in that order, with the 2 in the bulb.
- The longer a thermometer, the more restricted its contents. For example, the bulb in a 3-cell thermometer can contain any digit from 1-7 but the bulb in a 5-cell thermometer can only contain digits from 1-5.
- If the digit 1 appears on a thermometer, it must be in the bulb, as there are no lower digits to go below it. Similarly, if the digit 9 appears on a thermometer, it must be on the tip.
- If you eliminate the smallest possible digit in a thermometer cell, you may be able to eliminate digits from all cells higher up the thermometer. For example, if you had a cell that could contain 3456 and you eliminate the 3, that cell must now contain at least a 4 - which means the cell above it must be at least a 5, and the cell above that at least a 6, and so on. This also works in reverse with the highest possible digits in a cell.
Solve online here if you want: https://sudokupad.app/3vvfud2fzd
GZ is in a location where precision thermometers may be acquired and calibrated. Please be careful not to trample the garden while retrieving this cache; it is not necessary. Happy solving and hunting!