Friday Puzzles #261

Hurray!  It's another Christmas Tree Sudoku!

• Givens take the shape of silly decorations.  There is nothing else to say about these.
• The tree (anything shaded green or brown) acts as a fortress.  Which is to say numbers placed in the fortress must be strictly greater than those placed in the immediately adjacent  cells outside the fortress;
• Silver circles (fairy lights?!  Tinsel!?!) marking some pairs of adjacent cells are as in Parity Sudoku.  Which is to say one of the numbers to be placed must be odd and the other must be even.  Not all such pairs are marked
• White circles (erm, stars!?) marking some pairs of adjacent cells mean the corresponding two numbers to be placed must be consecutive.  Not all such pairs are marked.

Nice and easy.  Enjoy!

   #300 Christmas Tree Sudoku – rated hard

All puzzles © Tom Collyer 2009-14.

Friday Puzzles #260

Numbers placed in marked adjacent cells must be of opposite parity (i.e. one is odd, the other is even).  Please note that not all such cells are marked!

The trouble with if and only if conditions is that most of the fun is hidden behind the "only if" condition (think consecutive, XV, tens and so on).  These constraints still make for interesting puzzles simply as "if" constraints when designed properly.  They certainly look better.

Enjoy!

    #299 Parity Sudoku – rated medium

All puzzles © Tom Collyer 2009-14.

Friday Puzzles #259

Unfortunately I seem to be saving a lot of my better work for GM puzzles these days - and that doesn't just mean twisted symmetry either.  I'm not entirely how I feel about that, all things considered.  Enjoy!

    #298 Masyu – rated easy

All puzzles © Tom Collyer 2009-14.

Friday Puzzles #258

Bad news: I forgot to post last week.  Good news: I'll post twice this week!

Also, I managed to win* myself another nikoli time trial!  That brings me up to 5 (3 Sudoku wins, 1 Masyu win* and now 1 Shikaku win*).

(*) in this case, win means finish second to someone who'd won a time trial earlier in the year

    #297 Non-Consecutive Sudoku – rated medium

All puzzles © Tom Collyer 2009-14.