I suggest you go to Wikipedia
for that answer.
I've categorized the puzzles into different difficult level. The number in () are the iterations of inserting legal numbers into the puzzle after applying the reducingmethods. I'm trying different approaches and the one with the lowest iterations are recorded. The basis for trying is selecting the coordinate with the least possible available numbers in it. If there are more than 1 coordinate with the same amount of available numbers the different approaches steps in to pick the coordinate. This way it should almost show the possible choices you need to take solving the puzzle.
Super easy: SiSo
Very easy: SC
Very hard: SF, JF, SB, NS, FI, FC
Super hard: 1->
Startnumbers is the count of preinserted numbers in the puzzle. These are more commonly called "givens" or "clues".
Sure. Here's what you do:
You can link to a spesific puzzle with a link on the form:
Change 100 to the number of the puzzle. This way you can solve a puzzle and send it to a friend and see if he/she can solve it too. If you want to link directly to the page where you can solve the puzzle use:
In lack of a better description I've called them that. These sudokus are symmetrical, but the symmetrical numbers are the same (equal). These sudokus aren't very easy to generate so I don't have many of them.
Slider symmetrical is something I invented and named by Simes
. Have you ever played the 4x4 puzzle where you shall move the numbers 1-15 in the right position? This symmetry works a bit like that. The symmetrical boxes are B1->B9, B2->B8, B3->B7, B4->B6. The symmetry works only on these combos of boxes and not the whole Sudoku.
Optimal Sudoku are puzzles which are reduced to an optimal state. This means you can't remove more startnumbers. If you remove more, the puzzle will have more than one solution.
No. If you wish to download a lot of puzzles you should send me an email first.
No. This is a free service. If you wish to publish puzzles you have to buy them from me.