Logic Masters Deutschland e.V.

The Infiltration of Alamut Castle

This puzzle was made for a weekly Scojo setting prompt, in which we were tasked with setting a puzzle involving a battenberg Sudoku constraint. I took this opportunity to instead set a Sudoku hybrid with the pencil-puzzle genre Battenberg painting. I hope you enjoy it!

• Sudoku: place digits 1~9 once each in every row, column, and 3x3 box. Two (ciphered) Sudoku digits are given.
• Battenberg: shade some cells in the grid. Every battenberg clue indicates that the shading forms a 2x2 checkerboard-pattern around the clue. All battenberg clues are given.
• Outside clues: numbers around the grid indicate the sum of all digits in shaded cells in the corresponding row or column.
• (Non-standard) cipher: each letter C,R,...,S is assigned a distinct non-zero digit, to be determined. A "?" can always represent any digit, including 0. (In other words, "?A" could be the single digit number "A".)

A practice puzzle to clarify the rules if needed.