Logic Masters Deutschland e.V.

This was a birthday present for the one and only Bellsita! Thank you for inspiring the puzzle community, and for being one of the coolest people I've ever met! ♡

The ruleset is quite unusual, so I've included a smaller 6x6 puzzle without any cipher business for gaining intuition.

Rules: There are no rules!!!

Just kidding. They're below the next image.

Yes!! Now THAT looks more like a birthday puzzle! Here's how it works -

• Yin Yang: Shade some cells in the grid so that all shaded cells are connected orthogonally, and all unshaded cells are connected orthogonally. No 2x2 region may be entirely shaded or entirely unshaded.

• Japanese Sums: Place a digit from 1-9 (1-6 in the 6x6) in every unshaded cell such that no digits repeat in any row or column. Shaded cells do not contain digits. Clues in a row or column give the sum of each group of contiguous unshaded cells in that row or column. All clues are in the order their groups appear. "..." represents any number of clues, including zero.

• Cipher: The letters in "HBD BELLSITA" represent the digits 1-9. A question mark represents any digit, but a double digit clue cannot have a leading zero.

• Index Definition: For a cell in row R, column C, containing the digit X, that cell's column index is row R column X, and that cell's row index is row X column C.

• Supernatural Sums: In addition to normal summation, a column clue may instead sum the column indexes of each cell in a group, and a row clue may instead sum the row indexes. Any clue summing indexes cannot index shaded cells. Different clues in a row or column may be different kinds of summation, but they must still each point to a distinct group of cells.

Here is a visual example of how clues may look:

Best of luck! Enjoy the journey!

Penpa+ (6x6)
Penpa+ (9x9)

Thank you SO SO MUCH dumediat, mnasti2, and Myxo for testing this! ♡ ♡ ♡