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Logic Masters India announces November Sudoku Test — Renban Groups

Author : Zafer Hüseyin Ergan

Date : 13^th and 14^th November

Sudoku Types : 10 types, 1 6X6 and 1 9X9 from each type. Each Sudoku has Renban Group constraints

Length : 100 minutes

IB and Submission Link : http://logicmastersindia.com/lmitests?test=M201011S

and what exactly are the Renban Group constraints? :)

purifire - 2010-11-03 9:40 AM

and what exactly are the Renban Group constraints? :)

Please spend a moment checking the IB OR the submission page OR both :-)

Here it is -
Each Renban Group is a set of grey painted cells connected to each other, either orthogonally or diagonally. Each Renban Group must hold distinct consecutive digits, in any order. Renban groups may cross across 3X3 boxes / 2X3 boxes / irregular regions.

debmohanty - 2010-11-03 9:43 AM

Please spend a moment checking the IB OR the submission page OR both :-)

Here it is -
Each Renban Group is a set of grey painted cells connected to each other, either orthogonally or diagonally. Each Renban Group must hold distinct consecutive digits, in any order. Renban groups may cross across 3X3 boxes / 2X3 boxes / irregular regions.

Oops.. my bad... Didnt notice that the IB was already up :)

Administrator - 2010-11-03 9:24 AM

Logic Masters India announces November Sudoku Test — Renban Groups

Author : Zafer Hüseyin Ergan

Date : 13^th and 14^th November

Sudoku Types : 10 types, 1 6X6 and 1 9X9 from each type. Each Sudoku has Renban Group constraints

Length : 100 minutes

IB and Submission Link : http://logicmastersindia.com/lmitests?test=M201011S

In the shifted Sudoku, can it be assumed that the actual sudoku is a torroidal sudoku with the renban group constraint?? In the Ib the author mentions that the position of the 1-6 digits is incidental... not sure what is intended?

Rishi

Hi Rishi,

Yes it is actually a toroidal sudoku with the renban group constraint.

I marked the standard 2x3 blocks with red rectangles in the solution of the example. If you check
this you can see that digits 1 to 6 are placed exactly once into those red rectangles. But it is not
necessary which means that there may be duplicating digits in those red rectangles. Extra note just
try to explain this is an incidental situation. I have designed also a 9x9 shifted sudoku with renban
groups for the puzzle portal of German site http://www.logic-masters.de/. Here is the direct link for
that one:

http://www.logic-masters.de/Raetselportal/Raetsel/zeigen.php?id=000...

If you try to solve this one with given rules you'll see that there will be some duplicating digits inside
the standard 3x3 blocks

.

I hope the explanation is helpful.

Zafer

(shiftedsudwithrbg.JPG)

Attachments
----------------

shiftedsudwithrbg.JPG (22KB - 2 downloads)

Chinese version is available on http://www.sudokufans.org.cn/forums/index.php?showtopic=125
if you want to play examples online, click the image of puzzle on the left. ( please use IE7/8 or Chrome)

Thanks Zafer...

The explanation is indeed helpful :) Looking forward to the test..

Rishi

purifire - 2010-11-03 3:30 PM

Thanks Zafer...

The explanation is indeed helpful :) Looking forward to the test..

Rishi

solved the example on LM Germany and it was really a great puzzle.. :)

Rishi

Minfang Lin - 2010-11-03 3:11 PM

Chinese version is available on http://www.sudokufans.org.cn/forums/index.php?showtopic=125
if you want to play examples online, click the image of puzzle on the left. ( please use IE7/8 or Chrome)

for Chinese translation. It is also very good that the examples may be played online

I tried also playing in Firefox and I can say there was no problem also in Firefox

Regards,

Zafer

purifire - 2010-11-03 3:51 PM

solved the example on LM Germany and it was really a great puzzle.. :)

Rishi

Hi Rishi,

for your kind words

I'm glad you liked it. I wish you will also enjoy the actual
puzzle during the test.

Zafer

In the note for Shifted Sudoku, it says 'The numbers 1~6 must not occur in standard 2x3 boxes'. 'Must not occur' or 'May not occur'?

Hi Rohan,

It is actually stated that
"In the example numbers 1~6 is occured once inside standard 2x3 blocks. But it is not a MUST. Therefore there may be some duplicating digits inside these 2x3 standard blocks for 6x6 shifted sudoku (and 3x3 standard blocks for 9x9 shifted sudoku)".

In order to clearify this note I'll try to prepare a 6x6 shifted sudoku with renban groups in which there exist duplicating digits inside 2x3 standard blocks and try to share it here soon.

Regards,

Zafer

Here comes my new 6x6 shifted sudoku design.

Regards,

Zafer

(shiftedsudwithrbgex2.JPG)

Attachments
----------------

shiftedsudwithrbgex2.JPG (18KB - 8 downloads)

Rohan Rao - 2010-11-03 8:36 PM

In the note for Shifted Sudoku, it says 'The numbers 1~6 must not occur in standard 2x3 boxes'. 'Must not occur' or 'May not occur'?

Rohan, it is "May not occur".
It is basically a Toroidal Sudoku with special shapes of 2X3 or 3X3 blocks. [ So it should be much easier than a toroidal sudoku ]

Zafer, thanks for uploading another example.

Ok. Got it. Thanx Zafer and Deb.

Looking forward to this test :-)

Hi to all. Here comes the answer of my second 6x6 shifted sudoku example. You can see the duplicating digit or digits inside the standard 2x3 blocks.

Spoiler: show

Thanks Deb for your help on spoiler usage.

Regards,

Zafer

Edited by zhergan 2010-11-04 1:15 PM

I'm looking forward to this one and have managed to complete all the 6 x 6s in the instruction booklet apart from one - the Symmetric Unequal Sudoku. I expect I'm missing something really obvious but I can't work out which cells are 180 degrees symmetric to each other.

Can anyone try and explain it to me please? Thanks.

Hi,

In the symmetric unequal sudoku cells that are 180° symmetric to each other
cannot have same digits.

Keeping in mind that R corresponds to row and C corresponds to column; If
we talk about 6x6 R[n]C[k] can never have the same digit as R[7-n]C[7-k]
all n, k from 1 to 6 and if we consider 9x9 this time R[n]C[k] can never
have the same digit as R[10-n]C[10-k] for all n, k from 1 to 9 (of course
not both 5 same time).

Try to apply this rule once. You'll see it works. Hope it is more clear now.

Regards,

Zafer

And who are interested about symmetric unequal sudoku may try to solve my 9x9 example on LM Germany site with the following address:

http://www.logic-masters.de/Raetselportal/Raetsel/zeigen.php?id=000...

It is not a hard one also. You may try it as an exercise.

Zafer

Yes - I've got it now! Thanks for taking the time to reply - I've never come across this sudoku variant before. It's always great to come across a new puzzle type so I will go and try out the 9 x 9 now!

Regards. Christine

Some more Symmetric Unequal Sudokus from our older tests (without renban constraints)

From Classic Look Alikes

Click here to solve online

From Classic Look Alikes

Click here to solve online

from Mock 12

Click here to solve online

from Mock 12

Click here to solve online

Hi,
I cannot see any link to the IB for the test. Is there something that I am missing?
Munira.

lmunira - 2010-11-09 1:11 PM

Hi,
I cannot see any link to the IB for the test. Is there something that I am missing?
Munira.

If you are using a small screen computer, please scroll towards your right.
We are having this problem for a while now. High time we get it fixed :-)

Thanks,
Have got it. Silly of me.
Munira.

Renban is a puzzle type invented (so far as I know) by Inaba Naoki. You can find his examples at http://inabapuzzle.com/honkaku/renban.html . (All digits occur in each row and column, all cages are renban groups.)

The oldest sudoku variant with renban groups is Hanidoku ( http://www.hanidoku.com/ ).

Other renban at http://www.sachsentext.de/en/node/1156 and other hanidoku at http://www.sachsentext.de/en/taxonomy/term/162 .

Pyrrhon

Pyrrhon - 2010-11-10 1:51 AM

Renban is a puzzle type invented (so far as I know) by Inaba Naoki. You can find his examples at http://inabapuzzle.com/honkaku/renban.html . (All digits occur in each row and column, all cages are renban groups.)

The oldest sudoku variant with renban groups is Hanidoku ( http://www.hanidoku.com/ ).

Other renban at http://www.sachsentext.de/en/node/1156 and other hanidoku at http://www.sachsentext.de/en/taxonomy/term/162 .

Pyrrhon

Thank you for sharing history of Renban. I'm sure this will be informative to many players.

Also, for those who don't know, Pyrrhon's website http://www.sachsentext.de contains list of many many Sudoku variants. You google for any Sudoku variant, and sachsentext.de is most likely to be in 1st page.

Thanks Uwe for maintaining such a wonderful website.

debmohanty - 2010-11-10 11:55 AM

Thank you for sharing history of Renban. I'm sure this will be informative to many players.

Also, for those who don't know, Pyrrhon's website http://www.sachsentext.de contains list of many many Sudoku variants. You google for any Sudoku variant, and sachsentext.de is most likely to be in 1st page.

Thanks Uwe for maintaining such a wonderful website.

I also want to thank Uwe (aka Pyrrhon) for sharing information about Renban

. Some puzzlers may not be familiar with this subject. I also follow his great site http://www.sachsentext.de and learn about different variants

Uwe deals not only with sudokus and the site has a lot of different puzzle types also. But I know that solving Uwe's designs is always enjoyable. He shared some of them in LM German puzzle portal also. Maybe Uwe will manage to conduct another monthly sudoku contest for LMI in the forthcoming months. I think it will be a great.

Regards,

Zafer

Edited by zhergan 2010-11-10 2:04 PM

Munira (and everyone else with small screens): I think I've found a fix and have tested it out on my local copy of the authors page. Deb will be adding the fix to the test pages sometime soon, which should work for almost everyone. Sorry about the inconvenience!

Puzzle booklet (1 Title page + 10 pages of sudokus) is uploaded at the submission page. Here is the direct link

davmillar - 2010-11-11 11:37 PM

Munira (and everyone else with small screens): I think I've found a fix and have tested it out on my local copy of the authors page. Deb will be adding the fix to the test pages sometime soon, which should work for almost everyone. Sorry about the inconvenience!

Players with small screens - Please scroll towards right if you can't see the IB / PB.
David - thanks for helping in fixing this issue. We'll apply this technique in the next test.

Hi to all,

The test starts within almost 2 hours. I wish all participants
the very best of luck. I hope you enjoy solving the sudokus.

Regards,

Zafer

Nice sudokus. I liked the Renban concept applied to solving the sudokus.

@rakesh. what is ur score?

Lets not discuss scores here till the test is ON. This time, I think we are able to see all scores lower than your score in the results page.

rakesh_rai - 2010-11-13 9:08 PM

Lets not discuss scores here till the test is ON. This time, I think we are able to see all scores lower than your score in the results page.

Rakesh, you are correct. After taking the test, you should be able to see your score along with all others who have got < than you.

Very nice set of puzzles, I really enjoyed during the test. Thanks, Zafer!

Nikola

Rakesh and Nikola for your kind words. I'm glad you liked them.

Regards,

Zafer

Nice set of puzzles. Renban usage was neatly done. Thanks Zafer.

Thanks, Zafer! Very nice puzzles!

rakesh_rai - 2010-11-13 9:08 PM

This time, I think we are able to see all scores lower than your score in the results page.

Aha. This explains many things.

Good set of diagrams, thanks Zafer and thanks yet again Logicmastersindia.

Stefano

1. I naively thought from the Results tab that all the good sudoku players had been kidnapped and tied up in a closet somewhere as no one had passed my middling score.
2. Now I understand why I am the leader only in my own mind.
3. Was this explained somewhere ahead of time? I must have missed it.
4. Why is this the case and why dont you want us to see the others?
Thanks.

The Subro

it was a great test. and since we are only able to see the scores of people lower than us , i was in seventh heaven thinking i was topping . what a nice feeling it was. till rishi woke me up from my slumber and told me about the format of the result. but we must thank zafer for coming out with such lovely set of puzzles.

Zafer -- Quite an excellent set of puzzles, thanks for sharing them with us -

Best regards,

Dave

The change in score display is interesting.

Although it gives you a (false) sense of being at the top (at least till the test is underway), you do get to know the number of people below you. As for the number above you, it keeps you guessing till the end.

I like this change, as long as the scores are not discussed on the forum.

Nice puzzles, enjoyed solving them.

I like the change on the results page too... :)

Overall, it was another great experience for me. I have never done any sudoku puzzle that has Renban Groups in it. Unfortunately, I lost 42 points because the internet went down and i didn't finish typing the answer to Symmetric Unequal.

Complete results now available. Link, as usual, is http://logicmastersindia.com/M201011S/score.asp

Congratulations to Rishi, Fred and Jakub H. for topping in Renban Grouped Sudokus.
Rishi continued from his great performance in Hotpot (where he stood second behind Thomas S.) and finally, we have an Indian at the top of the table.
There is very little to choose between Fred and Jakub with only few seconds differentiating them.

Nice to see Rohan completing all the grids well ahead in time.

deu, cpickerel and willwc played really well to complete all the grids.

Few more players had chance to complete all the grids, but minor mistakes crept in (especially Jason who lost the 2nd place because of a mistake in 6X6 Symmetric Unequal)

188 participants, and 167 non-zero scores - both better numbers than any LMI Monthly Sudoku test.
Thank you everyone for participating.

Please share your feedback about puzzles and / or rate them, if you have not done so yet.

Zafer, thanks a lot for the wonderful sudokus. I'm sure everyone enjoyed them.

Also thanks
to Ours Brun, who pre-tested the Sudoku, he completed all the grids in very impressive time.
to Rakesh Rai for reviewing the IB completely.
to David for designing the test logo.
to Rakesh, Rohan and Tejal for taking the test earlier in the weekdays, to find out potential issues because of our recent database upgrade. Fortunately, there were none.

Rather surprisingly, the two most error-prone sudokus were both 6x6 - non touching and symmetric unequal.

rakesh_rai - 2010-11-15 10:19 AM

Rather surprisingly, the two most error-prone sudokus were both 6x6 - non touching and symmetric unequal.

It is indeed little strange. Also the low pointer, Shifted Sudoku 9X9, is solved by very few participants. While viewing 'live' results, I could see that among those who solved it, most players skipped this Sudoku in the beginning and returned to it at a later point in time.

I always attempt such sudokus (like Shifted and toroidal sudoku) in the end, which usually means I end up skipping them because the timer runs out anyway. I think the main reason is that these require you to think "unnaturally". So you postpone it for as long as possible.

Maybe, we can have some contest in future with only such variations....then there is no escape.

Hi to all,

Thanks for positive feedbacks

I'm glad most of the puzzlers enjoyed this renban concept
inside sudoku grids. Knowing these renban groups and the candidates for digits inside these
groups your solving speed increases I think. So it won't be wrong to think that they are like
catalysts for complete solving process for a grid. Classical sudokus and variants have different
constraints which limit the possibilities for a single cell and with the help of renban group contraints
these possibilities become more restricted. These are my thoughts about renban groups.

all puzzlers for participating. I want to congratulate also Rishi, Fred and Jakub H. for topping

Really well done.

Thanks to LMI for hosting this competition, Bastien VIAL-JAIME (aka Ours brun) for test-solving the grids (and also amazing timing), David Millar for designing this very nice logo which fits well for the renban concept. I also want to thank Deb Mohanty for all kinds of support and help about the test.

Regards,

Zafer

Edited by zhergan 2010-11-15 12:46 PM

Zafer,

Thank you for producing a beautiful set of puzzles. I found the logical process of solving these very original. Also rather slow compared to many others, but it was thoroughly enjoyable. It was nice to have some rarely seen (by me) Sudoku ideas like Diagonally Non-consecutive and Argyle take their place in this contest. Congratulations to setter, testers and speedy solvers.

I have to say that I didn't like the new results page. Too much of a tease for my liking. I'd rather know nothing (apart from my own score) until the contest is over or else see all the scores like before.

David McNeill.

thesubro - 2010-11-14 8:15 AM

1. I naively thought from the Results tab that all the good sudoku players had been kidnapped and tied up in a closet somewhere as no one had passed my middling score.
2. Now I understand why I am the leader only in my own mind.
3. Was this explained somewhere ahead of time? I must have missed it.
4. Why is this the case and why dont you want us to see the others?
Thanks.

The Subro

rakesh_rai - 2010-11-14 11:22 AM

The change in score display is interesting.

Although it gives you a (false) sense of being at the top (at least till the test is underway), you do get to know the number of people below you. As for the number above you, it keeps you guessing till the end.

I like this change, as long as the scores are not discussed on the forum.

Tejal Phatak - 2010-11-14 11:56 AM

I like the change on the results page too... :)

David McNeill - 2010-11-15 2:43 PM

I have to say that I didn't like the new results page. Too much of a tease for my liking. I'd rather know nothing (apart from my own score) until the contest is over or else see all the scores like before.

David McNeill.

Thank you everyone for your feedback on the new results page. We wanted to have a bit of surprise, which resulted in this experiment (and thats why it was not announced in the forum earlier)
It has received mixed reactions in this forum and also in other forums (ukpuzzles, sudokuvariante.forumactif.com)

For the next test, we hope to change it to what most players would want to see.

debmohanty - 2010-11-15 5:33 AM

rakesh_rai - 2010-11-15 10:19 AM

Rather surprisingly, the two most error-prone sudokus were both 6x6 - non touching and symmetric unequal.

I did this and never got back round to finishing it during the time (solving unofficially after everything had finished). As I said on our own boards, it certainly didn't feel like it was worth only 2 more points than the classic!

Congrats all round, firstly for the organisers in hitting a record turnout, and secondly for Zafer for providing an entertaining set of puzzles!

Too bad I couldn't start in time. I was doing pretty well for the 50+ minutes I had to solve.
The shifted 9 by 9 wasn't hard per se, but all the openings lay in the wrapped around nonets and were easily missed. I found the symmetric unequal hard to see. also messed it up it seems.

Thanks to Zafer for organising this wonderful sudoku test. Grids were nice and I liked the concept of "renban groups" (which I didn't know before).

Thanks to all LMI team, which allows such tests to take place. I don't know why, but I can do very good results on this site

.
Because of the new result page, I really believe I was 1rst, seeing all these famous players behind me

, but it misses one name: congrats to Rishi, very well played !!!

The only disappointment was the low participation of members of french forum "sudokuvariante". Even so I had opened a topic and made the announcement on the portal, and Bastien said grids were beautiful and not too hard...

Fred

Fred - read about your strategy (solving 9X9 grids first, and then 6X6 grids) in sudokuvariante.
Very interesting indeed, given that some of the 6X6 grids were high valued

In Hyderabad, all solvers got together to solve it. It was really nice meeting other solvers and discussing strategies post the test.

The Venue was Euro School (run by Jaipal ). Best part was we had 9 new people participating.. 7 school children and 2 teachers!!!!!!!!!!!!!!! Before we got to the test and while we were waiting for other solvers, we had a nice interactive session wit hthe school children and teachers where we discussed the variants and how we can solve them. The enthusiasm shown by the kids was really great to see.... Neeraj, Jaipal and I spent some time with the kids and they loved it....

Post the tst we all sat down and discussed how each one of us went through the puzzles and the approach adopted. The school management was happy with the interaction and so were some of the parents who had come with the kids... We are planning to have more sessions with the school kids and are working out details how to improve their interest in the game and make them solve more...

Thanks to Jaipal for arranging it and the lovely lunch...

Rishi

Congrats to everybody, particularly Rishi, Fred and Jakub H. of course.

Thanks to Zafer fo this nice set of puzzles, none of them was really hard but I had fun on every grid, which I really appreciated.

And, again, thanks to Deb and whole LMI team for this great job. You really do a big work to make sudoku evolve and gain popularity.

Here is a screenshot of the results of the school kids who attempted the Renban... It was a mighty effort from them, keeping in mind that they were looking at variations for the first time ever.... With regular practice I am sure they will climb the results ladder.

(HydResults.png)

Attachments
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HydResults.png (22KB - 3 downloads)

It is interesting to note that most kids solved the NoKnight Step Sudoku (apart from Classic). Some kids solved the Diagonal as well.

debmohanty - 2010-11-18 9:33 AM

It is interesting to note that most kids solved the NoKnight Step Sudoku (apart from Classic). Some kids solved the Diagonal as well.

Before the test when we were having a session with the kids... Diagonal and AK were the most discussed... The kids understood the concepts very well too and hence majority attempted it.

purifire - 2010-11-18 9:36 AM

debmohanty - 2010-11-18 9:33 AM

It is interesting to note that most kids solved the NoKnight Step Sudoku (apart from Classic). Some kids solved the Diagonal as well.

Before the test when we were having a session with the kids... Diagonal and AK were the most discussed... The kids understood the concepts very well too and hence majority attempted it.

Nice to see this kind of enthusiasm. Hope to see more of this in future.

Rohan Rao - 2010-11-18 3:56 PM
Nice to see this kind of enthusiasm. Hope to see more of this in future.

You guys should plan to have one in Mumbai / Pune region. Target for December Sudoku test (around Xmas)