Logic Masters Deutschland e.V.

This puzzle is a special tribute to my father-in-law, who passed away a few weeks ago. He was the most skilled man with his hands, very fond of do-it-yourself, had built his own house and helped me build mine, knew and taught me countless tricks in woodworking, plumbing, welding, electricity... He was not the kind who would sit behind a desk or in his couch doing puzzles, and I don't think he ever ventured further than the easy-classic-sudoku-with-morning-coffee of his newspaper, but I think he would still have appreciated the looks and dynamics of this circuit-board grid. This is for you, Jean, you cut the power way too early...

Now about this puzzle, 4 linked grids with digits from 1-9 that have to be discovered by the solver. Each grid has its own internal logic, but they all need infos from others grids for resolution. I'm really proud and happy with how it turned out. It could be quite a long solve. But I hope and think it should be very satisfying to see it all come together. Only the lines are bifurcating here, not the logic ! I will put a walkthrough of the main intended steps in a hidden comment if you're interested.

Thanks to lerroyy and Paquet Voleur for testing it !

Rules :

- Normalish sudoku rules apply : in each 6x6 grid, place exactly 7 of the digits 1-9 (not necessarily the same 7 digits in all grids), so that each of those digits appear once in each row, column and box. To allow this, there is an S-cell in each row, colum and box, that contains 2 digits. Do the same in the 4x4 grid with 5 digits from 1-9.

- On renbans and region sum lines, the value of an S-cell is the sum of its 2 digits.

- Grey areas outside those grids do not contain digits.

- The switch (dashed yellow square) is part of the big renban going around the grid. It must contain one digit from 1-9. It is not a S-cell.

- Renban : Each red line is a renban and must contain a set of non repeating consecutive integer values in any order (e.g : 12-9-10-8-11). Digits can repeat on the lines if allowed by other rules (e.g : 7-8-27-6-28).

- Note that 2 separate renbans cross between the 2 left grids. Renban 1 : R6C2 -> R1C3. Renban 2 : R6C4 -> R1C2.

- Region sum lines : Blue lines must have an equal sum N within each region they pass through. If a line re-enters a region, each segment sums to N separately.

Solve with Penpa.

Solve with CTC webapp.

I recommend solving with Penpa, because it has answer check on S-cells too, and the pencilmarks show better on the lines.

Enjoy ! And consider giving feedback if you appreciate the puzzle !

You can check out my other puzzles here if you liked this one.