It’s a big one, and it’s anchored by Gravity Cages at the bottom. While these cages don’t directly affect anything else in the puzzle, I like to imagine they’ll combine to form a black hole, pulling everything in all four grids into a single cell.

Rules:
Normal Gattai-4 rules apply. That is, there are four overlapping 9x9 Sudoku grids. Within each Sudoku grid, each row, column, and 3x3 box contains the digits 1-9. Overlapping boxes are shared between the overlapping grids.
Digits within cages sum to the small number in the top left corner of that cage.
The marked diagonal contains the digits 1 to 9 exactly once.
Renban: Digits on each pink line form a set of non-repeating consecutive digits in any order.
Gravity Cages: Within cages marked with an arrow, digits do not repeat, and larger digits are pulled in the direction of the arrow. That is, no digit is higher than the caged digits below or to the right of it.
Digits on thermometers strictly increase from bulb to tip.

Estimated difficulty: 3 out of 5

Solve on SudokuPad

When the arrow points to the bottom right, the cage is a Young Tableau, but something’s gone strange in this puzzle, and gravity seems to be pulling every which way. Some cages are upside-down or reversed or both, but the arrow always points in the direction of strongest gravitational attraction.

Rules:
Normal Sudoku rules apply.
Within cages, digits do not repeat, and larger digits are pulled in the direction of the arrow. That is, within each cage, rows increase from either left or right, while columns increase from either top or bottom, both in the direction the arrow is pointing.

Estimated difficulty: 2 out of 5

Solve on SudokuPad

With the largest digit in the bottom right corner, these are also known as Young Tableaux. I’ve added an indicator arrow both as a reminder of the Young Tableaux constraint, and as a hint that future Gravity Cages might not always have the arrow point in that direction.

Rules:
Normal Sudoku rules apply.
Within cages, digits do not repeat, and larger digits are pulled in the direction of the arrow. That is, within a cage, rows increase from left to right, while columns increase from top to bottom.

Estimated difficulty: 1 out of 5

Solve on SudokuPad