Daily Clone Regions Sudoku
The extra rule
The two shaded shapes are identical: matching cells hold the same digit.
Two shapes are shaded, one red and one blue. They are the same shape, and whatever digit sits in a cell of one sits in the matching cell of the other.
This is the only rule on the site that makes two cells EQUAL rather than different, so the usual habit of ruling digits out does not help here. What helps is carrying a digit across: solve a cell in one shape and you have solved its twin.
The shapes never share a row, a column or a box, because two cells that see each other could not hold the same digit.
Controls
Click a cell and type a digit, or use the pad. Space toggles pencil marks. Arrow keys move. Progress saves in this browser as you go, so you can come back to the same puzzle later today.
Solvable Without Guessing
Every puzzle here was generated and then handed to a solver that is only allowed techniques a person can use. If it could not finish the grid without a guess, the puzzle was thrown away rather than published. That also makes the answer unique, because every digit it placed was forced.
More to Play
There is also a kropki sudoku, a xv sudoku, a greater than sudoku, a nonogram with hand drawn pictures, and 2048. All of them are on the games page, and the solvers for real objects are on the puzzle tools page.