# Latin Square Puzzle - Difficult

Follow on puzzle from the introductory Latin square puzzle post.

The rules

1. It’s a Latin square like sudoku, so there must be the numbers 1-9 exactly once in every row and column.

Notice that each dark vertical line divides a row (1x9) into three 1x3 blocks.

1. In every row, within a 1x3 block, you can only have one number from each triple {123}, {456},{789}.

So essentially in a row you have to space out the numbers 1,2,3 into the three divisions of the row.

Eg, in the first row, the first 1x3 box contains a ‘3’, therefore in the next box you cannot have a ‘1’ or a ‘2’. Similarly the same 1x3 box contains a ‘7’ so you cannot put an ‘8’ or a ‘9’ in the box beside the three.

There should be a unique solution from the construction.

Enjoy :)

• This is just a sneaky encoding of a sudoku puzzle! A sudoku puzzle's clues can be given as a list of ordered triples (x, y, v), meaning value v is written in row x and column y. By taking all these triples and reversing them, replacing each (x, y, v) with (v, y, x), the block condition turns into your rule #2. Mar 24, 2018 at 21:30
• @MikeEarnest :P I came across this trying to think of ways to transform some of the harder sudoku into something potentially easier. It’s not much easier to deal with except in very special situations. Mar 24, 2018 at 21:48

The puzzle is pretty good and when trying to solve it I get confused with sudoko. I am not sure if my answer is correct.

• two '9's in block 2?? Ah never mind I see the 3x3 block rule is void here... Mar 25, 2018 at 5:54
• Double checked, looks correct. How did the two wildly different handwritings happen, by the way?
– Bass
Mar 25, 2018 at 7:06
• Actually both are my handwriting.....it is just that one was written with pen and the other with pencil Mar 25, 2018 at 8:09