STUB

Rules:

This puzzle is a combination of a cryptic Japanese Sum Cave and a Pentominous, with one grid lying on top of the other.

Japanese Sum Cave: Clues outside the grid give the sums of connected digits between empty cells in the correct order. No digit may repeat in a row or column. Same letters stand for same digits, different letters for different digits, and ? stands for any digit 0-9, but no clue may have a leading zero. (Point of clarification: Digits placed in the grid are 1-9). The filled cells of the Japanese Sums puzzle form a cave: all filled cells are connected and every empty cell is connected to the edge by other empty cells.

Pentominous: Every uncircled cell in the grid must belong to exactly one pentomino, and no two pentominos of the same shape may touch. Rotations and reflections of the same pentomino are the same shape.

Interaction: For all circled cells, the letter corresponding to its digit indicates the shape of the pentomino at that location. If a circled cell has no digit, then no pentomino may enter the cell. Clarification: the only cells that may not have pentominos are empty circled cells.

Example: If R1C3 is is a 7, and T=7, then R1C3 must belong to a T pentomino.

Note: Two of the twelve pentominos do not have digit assignments, but these pentominos may still appear in the Pentominous. Each digit from 0-9 is assigned exactly one letter, as standard.