Star Sudoku
Star Sudoku
This puzzle features cells that belong to only one "generalised rows" (n.b. it doesn't really make sense to talk about rows and columns for this kind of grid), and aren't crosschecked by another.
Re: Star Sudoku
It has the related feature that some rows have only 8 cells (which can be a potential problem, too).
I remember having seen this variant (in french magazine, very long time ago) with rule that each 8-cells rows was completed by the touching single cell.
The primrose sudoku (this geometry: http://sudokuvariante.blogspot.com/2016 ... udoku.html) has the same property of having some cells belonging to only one generalised row (more than one cell per region: there are 9 such cells for only 5 regions), but in counterpart, there is a - perhaps not well-known - technique to notice that these cells form an extra-region. Here all rows have digits from 1 to 9, in contrary to star sudoku.
I remember having seen this variant (in french magazine, very long time ago) with rule that each 8-cells rows was completed by the touching single cell.
The primrose sudoku (this geometry: http://sudokuvariante.blogspot.com/2016 ... udoku.html) has the same property of having some cells belonging to only one generalised row (more than one cell per region: there are 9 such cells for only 5 regions), but in counterpart, there is a - perhaps not well-known - technique to notice that these cells form an extra-region. Here all rows have digits from 1 to 9, in contrary to star sudoku.