Logic Masters Deutschland e.V.

This Puzzle is a hybrid between Sudoku and the pencil puzzle Aquarium. It is meant to be an introduction to a bigger puzzle (9x9) I'm currently working on. This is also the one of the first puzzle I ever set.

Rules:

• Normal 6x6 Sudoku rules apply.
  Numbers from 1 to 6 must occur once in each row, column and 2x3 region.
• First row and first column act as clues for an Aquarium puzzle in the remaining 5x5 region (r2c2 to r6c6).
  Aquarium:
  Each cage is an Aquarium, and the cells must be coloured green (air) or blue (water) according to the following rules:
  • Any cells in the same row and Aquarium must be the same colour;
  • Any green cells must be above any blue cells in an Aquarium;
  • The number in the first row or first column indicates the number of blue cell in the respective row or column.
• Additionally, inside an Aquarium any digit underwater (in the blue area) floats according to its value. A lower digit can never be in a row below a row containing a digit of higher or equal value. This applies to the full row.
  Digits in the air (green area) do NOT follow this rule, their position is not constrained by digits in the other rows.
  Digit position is not constrained by digits in other Aquariums.
• Additionally, winkles (sea snails represented as 6 and 9) must be attached to the side of their Aquarium according to the following rule:
  • "6" winkles must be attached to the left side of the Aquarium;
  • "9" winkles must be attached to the right side of the Aquarium.
  In other terms, this means all "6" must have an Aquarium wall on their left and all "9" must have a wall on their right.
• Notes:
  • Digits CAN repeat in an Aquarium as long as all the other rules are followed.
  • "9" winkles do not appear in this size of puzzle!

Puzzle can be tried at f-puzzles here or CTC (includes solution check) here