This Chaos Construction puzzle was inspired by KNT's Japanese Sum Cave Cipher series.
Normal Irregular Sudoku rules apply, but the regions must be determined by the solver. All regions are orthogonally connected groups of 9 cells.
Shade each cell in the grid either yellow or blue. All cells in a region must be the same color.
Clues outside the grid are Japanese Sums clues. For each row and column, either all or no clues are provided. Clues above the grid indicate the sums of contiguous yellow cells in that column; each group is separated by at least one blue cell. Clues to the left of the grid indicate the sums of contiguous blue cells in that row; each group is separated by at least one yellow cell.
Clues are ciphered. Each distinct letter represents a unique digit from 0 to 9. A "?" can be any value 0-9. For a two digit number, the first digit may not be 0.