Yes indeed. I could not spot that...

A general query guys....is it advisable to put more than 2 possible numbers in a box? Initially i was not in the habit of putting possible numbers in a box.In fact i hated that since i felt it made the whole sudoku very clustered.But i have realised that it is impossible to solve sudokus of greater difficulty without making a note of the possible numbers that occur in a box.But still is it advisable to write 3-4 numbers in a box and try to solve it if u get stuck, or to just write numbers where you get only 2 after eliminating the rest..This is something which i had always wanted to know from others because even after putting 2, i have got stuck in many a sudoku and the whole thing gets clear only when i put 3 numbers ...want to be sure that sudokus can be solved without writing more than 2 possible numbers in the box....ideas are welcome...

Its about the method that suits you best. Personally, I don't like using pencil marks at all. I do better on sites without pencil marks, and I try but I can't stop myself from using them subconsciously when they are there as a part of the interface(been trying to). I've talked to others though and the normal thing is to note down numbers to keep track. So I suppose you'll find this way easier. The difficult ones need a lot of pencil marks, because to add difficult tricks, the creator would have to use a larger group of numbers in the grid and solving them requires an understanding of that entire group. So there's nothing wrong in entering 4-5 pencil marks in a cell as long as you don't end up confusing yourself(which is my problem and why I'm faster without that).

Edited by prasanna16391 2012-09-28 3:58 PM

@ kishore : from where do you get those sudokus ? they are pretty interesting to solve. can you share the source ?

I take them from fed sudoku...choose puzzle blogs from LMI home screen -->Fedsudoku--->sudoku archive--->classic printable....
They are my daily dosage of tablets for improving sudoku skills.

Akash is a regular there, he's just not been able to do them lately so didn't know I suppose. Anyway, I'm a regular there too. There's other sites as well with daily sudokus like Sudokucup, mindoku. These 3 are my daily routine anyway. Related to your earlier pencil marks question, mindoku's interface doesn't have pencil marks.

the way please in this


Edited by kishy72 2012-10-06 9:57 PM

oh my !!!!

Just by going the marks you have done (and assuming that they are correct), where do you put 3 in Box2?

However, I think you have gone wrong somewhere. I couldn't resolve the bottom 3 rows so early in the solve.

i have addled the sudoku so much that i could not see that direct spotting...and yes i have gone wrong. I started from the beginning again and i saw where i went wrong ....Thnks deb!

So fellas another of those tough computer generated ones where i feel it has managed to give the bare minimum number of numbers required .... a tough nut to crack for me....tried for 28mins.....totally warped .....shw me the way Lmians!!



Edited by kishy72 2012-10-22 7:42 PM

and if possible post a link where i can see these versions guys
Untouchable sudoku,Disjoint groups ,Symetric unequal , Antiknight
Queens ,Quadro ,Touchy , DuoDoku.... not even heard of some of these variants...planning to take part in sudoku cup want to try atleast one of each of these versions(hopefully) before the test.

Firstly the Classic - I remember this one. What I did while solving was focus in the first box. By process of elimination, you get that R2C1, R2C3 can only contain either of 4-6-9. You've already marked R2C7 containing 4-6. This makes a triplet and eliminates 6 from the 2-6 in R2C5, so you have a 2 there. Should be ok after that.

For the variants - You can look at past Monthly tests for some. I think I remember off the top of my head an Anti Knight in Sudoclones and a Queen Sudoku in Diagonal Vision. Apart from that, you have Disjoint groups in the Fed Sudoku site itself, in the Alternatives section. So too Quadro I think. There's also this site(Where disjoint groups is called Offset, Symmetric Unequal is I think No Mirror).

Edited by prasanna16391 2012-10-23 1:05 AM

You can also find some of them in the monthly test authored by Jan Mrozowski 2 years ago, called "Classic Look-Alikes", it's basically the same concept as the 1st round of sudokucup:

http://logicmastersindia.com/lmitests/?test=M201007S

Fred

Thnks prasanna and Fred for the links ...did not spot the 469 combination in R2C1 ......and by the way took this Queens sudoku from Diagonal vision....valued at 85 points i assumed initially that is too much for a simple sudoku (atleast it appeared to me like that with so many numbers) But i soon realised that this sudoku is worth its weight in gold......tried at 3 different times today to give my mind a break and still could not proceed beyond this point.....i could not use the queen constraint at all with just 1 9 locked till this point.

and in symmetric unequal what does cells 180deg symmetric to each other mean..????totally blank....could not make out head or tail out of it...kindly explain guys..

The queen sudoku of diagonal vision's instructions booklet is a bit too hard... It's my fault.
We discussed about it there: http://logicmastersindia.com/forum/forums/thread-view.asp?tid=451&s...

Fred

R1C1 is symmetric to R9C9, R1C2 is symmetric to R9C8, R2C1 symmetric to R8C9, etc... does it help?

Fred

So i am not the only one stuck it seems! But Beautiful theme nevertheless....similar to what u do in a chess game.......think ahead and see if it is advisable to go with that continuation...perhaps thats why this sudoku is rightly named queen sudoku....i was looking for a logical continuation....did not look for a contradiction at all....

So going by the same logic R5C1 is symmetric to R5C9 ,R5C2 is symmetric to R5C8 etc...and the only cell symmetric to itself in the entire grid is R5C5...?!

That is correct. Now all the additional rule says is "If two different cells are 180⁰ symmetric to each other, they must contain different digits".
More examples: mock12 IB & PB - http://logicmastersindia.com/lmitests/?test=mock12

not able to touch the solution in this untouchable sudoku....cells with same digits dont touch diagonally..first sudoku of this variant which i had tried ...where am i missing the trick here?


Edited by kishy72 2012-10-29 11:01 PM

Kishy: BE CAREFUL NOT TO POST THE SUDOKUS OF A COMPETITION BEFORE IT IS FINISHED !

The competition is now finished, but it was not the case when you posted this one.

That being said, try to place the 2 in row 5, and then you can place lot of other digits

Fred

Kishy72, Consider this as your first and last warning. Never post puzzles from LMI / other sites while the competition is running. Always wait for few hours after the competition ends.