Logic Masters Deutschland e.V.

The Lernean Hydra is a serpentine monster from Greek legend, with nine heads. You’ve been given nine arrows with which to slay the hydra, but first you must locate each of the nine heads.

The rules are as follows:

1. Normal sudoku rules apply.

2. Normal thermometer rules apply. Digits must increase along thermometers as they move away from the bulb.

3. Normal killer cage rules apply. Digits in a cage must sum to the number in the top left corner at the top of the cage. Digits cannot repeat within a cage.

4. Normal arrow rules apply. Digits along the arrow must sum to the number in the circle.

UNIQUE SUBSET – Each of the arrow clues must be different. They effectively form a disjoint subset of their own.

5. The Hydra…

i) The hydra body starts at the 1 in box 8 and moves orthogonally throughout the grid.

ii) The hydra cannot touch itself orthogonally, but it CAN touch diagonally.

iii) The hydra heads are located on each of the 9s.

iv) The hydra must split if it crosses a 2 or 3 in the grid, into either two or three separate heads. (It does not have to cross every 2 and 3, nor even a 2 or 3 in each box).

v) The hydra cannot move off the edge of the grid.

vi) The hydra must move through the green cell indicated in box 5.

Slay the Hydra on f-puzzles

Or on the CTC App

An example of how the Hydra heads split.