Sudoku World Championship 2012

This year the Sudoku World Championship took place in Kraljevica, Croatia. I decided to take advantage of the proximity to Italy and therefore I also traveled a bit to Verona and Venice, and thanks to the good train connection it was easy to get to Trieste, close to the Croatian border (Kraljevica is located about 100km from the Italian border). I arrived at the competition venue earlier than the other team members, because one member of the Italian team drove there by car and thanks to our team captain's good acquaintances with him, we managed to finish the last 100km in his car. The other team members arrived in Trieste earlier (in the morning already), but due to the poor organization of the organizers, all the people who came to Trieste were collected by bus only at 8 pm. So it was a very tiring arrival for all the other Estonian team members and, as a result, they did not arrive by the time the competition guidelines were discussed. As a result, in quite a few rounds, our men/women had poor results in the first rounds. I'll write about the overall impression, the location, and the competition right away...

The competition venue was the Uvala Scott** hotel. The hotel itself is located in a very picturesque bay surrounded by cliffs. As a backdrop, a very gorgeous arched bridge has been built next to the hotel, which is very gorgeous in terms of location. The hotel rooms, however, do not bear much criticism. We were promised that we would get renovated rooms, but the question arose as to when they were renovated. Each room had 3 beds, a table and a refrigerator pulled out of the wall and that was all. The bathroom was like any other bathroom and it seemed that some kind of renovation had been done there, but sitting on the potty was more of a balancing exercise - it was not particularly attached to the floor. The rooms themselves were located a bit away from the main hotel, about 100m away. Since I stayed in the hotel room for an average of 6-7 hours a day and only used it to sleep, this stuff did not bother me much. The creatures the size of fingers, about 25-50 feet long, were running around in the bathroom.

When I saw our team representatives on the first night after the Q&A round, it turned out that they had first waited at the airport for a long time and when I asked what the organizers (2 older ladies) were expecting, and when I got the answer that they were Greeks, it turned out that they were already on the bus. To top it off, before arriving, the ladies made a small 15-minute coffee stop at a gas station and the others just sat and waited on the bus. Here is a big minus for the organizers. They should have sent 2 buses to Trieste, one for lunch and one for dinner, and they shouldn't have been joking. Most of the people who came via Trieste would have arrived for the Q&A round. The second big minus, however, was the content of the hotel, as I already mentioned in the previous post. Considering the participation fee (which is the same every year) and comparing the hotels of previous years, the difference is enormous. But all of that was forgotten when I entered the room where the competition was supposed to start. The room was obviously small for 150 people. Not to mention, the lighting was poor and there were no curtains on the top row of windows - which essentially meant that either you had poor lighting, or at some point a bright beam of light would fall on your paper, making solving quite uncomfortable. In addition, the tables were arranged in pairs in a chess order and the aisle was quite narrow - ideal for seeing which solution the person sitting next to (diagonally - in front) would get. But I believe that the participant sitting next to/behind me was not looking at my work, because he was a pretty tough solver who wouldn't go out of his way for something like that.

This time it was decided that the theme of the competition would be Disney. And so the theme of the first round was Pinocchio. The Sudokus were all classic, but there were also numbers written in three different boxes in a different (larger and brighter) font. 2 of these numbers were correct and fit the solution, and the third was wrong. You had to find the wrong one yourself. In addition, the Sudoku had three boxes marked with the letters A, B and C and the goal was to solve the Sudokus for as long as you could find out the numbers that went into these boxes. So you didn't have to solve them until the end - which is unacceptable in my opinion in the general ethics of solving Sudoku. You could have just let the Sudokus be solved. But the result was good, I finished second and besides me, 2 other competitors finished, who turned out to have some mistakes somewhere. A very good start for a competition, Jakub Ondroušek from the Czech Republic came in first with 75 points, and I came in second with 71 points. The third had 50 points left.

It was a round where 3 sudokus were connected in such a way that the marked two adjacent numbers had to be the same in all three sudokus. I managed to complete 7 out of 10 triples and got a decent 95 points, which gave me a good 5th place in this round. Jakub Tsehhi and Jan Poola got 101 points, Chen Cen 109 points, which is not a bad loss, but Kota Morinishi scored 138 points, which is a very impressive amount. So Kota caught me and increased the lead to about 30 more points, Jakub slipped a little further ahead and Jan came a little closer. The rest stayed further away.

In Snow White and the 7 Dwarfs, you first had to solve 7 sudokus, mostly 6x6. However, these were quite complex variants and it still took some time. In addition, these 6 were connected by 7 dwarfs, each dwarf had its own value (1-7). Each sudoku had 2 dwarfs and 2 marked cells. You had to figure out which dwarf was in which marked cell. The sudokus were of a special shape, with inequality signs, deficit (6x6 sudokus with 5 cell-sized areas one single square), halved squares (some squares are halved diagonally in the middle), sudokuro (similar to kakuro), snowflake (where the numbers were 1-7) and tightfit sudoku (in a 6x6 grid, 3 cells in each row and column are divided in half and the numbers are 1-9). Once these were solved and the values for the dwarfs were found, the Snow White Sudoku (a special diagonal) had to be solved, where the clues given by the dwarfs had to be placed. However, the organizers had set the stage quite well. It was not a logically solvable Sudoku and obviously some variant had to be tried out. While the round lasted 45 minutes, and in 25 minutes I was able to collect 60 points with small Sudokus, in the remaining 20 minutes I was not able to collect the remaining 30 points. The Japanese surprised us here, and 3 out of 4 solved this task. Kota flew even further with 93 points, because since I also had one of the small ones wrong, I got 51 points (most other competitors got 60 points).

In this round, 15 specially shaped sudokus were given, and each sudoku had pictures of 9 characters from The Muppet Show. Throughout the round, each Muppet had its own specific value, and each sudoku contained exactly 9 different muppets. When the round started, as expected, serious paper shuffling began, because each sudoku was on a different page and the solvers started finding values for the muppets. There was active shuffling for about 5 minutes, and then the shuffling gradually began to quiet down. A terrible start to one round, because when I got my muppets, the shuffling seriously interfered with solving. In addition, there were very difficult sudokus stuffed in, so it was not necessary to make such a fuss. The results showed this. I managed to solve 7 sudokus, which gave 52 points. Jan probably managed to do at least 4 more, because 86 points is a good result and Kota's 74 also stands out. Some still got over 60 and the result should be about 10th place for me. Jakub surprisingly got 28 points. As a result, Jan passed me and I passed Jakub and Kota got even further away. I believe that I was able to do this round significantly better, because I was able to solve one sudoku properly in the meantime. Looking at the results of my competitors, you could be satisfied with at least 60 points. But this is the way of the competition, you only have one chance and if you don't use it, it's your fault. In addition, since at the end of all 7 rounds only the results of the first two rounds were known, even if I was in 3rd place, the following rounds did not inspire much optimism regarding a possible final place. But now I'm going to bed and I'll write about the next 5 rounds (3 individual 2 team ones) and the finals tomorrow morning.

The round included mathematical variants (14 in total), where addition, multiplication, subtraction and division varied. I felt weaker in two variants, where the idea was that areas of 4 cells were marked in each and they had to contain a multiplication operation (AxB=CC). In addition, there was one addition task, where both areas of 8 cells had to have the same amount. Fortunately, I found a system for solving this variant before the World Championship and left it for the penultimate. The only place where I ran into problems in this round was while solving the killer sudoku. When 2/3 of it was solved, I reached a point where the only way to continue was to write two identical numbers in the same area. Since the classic killer does not allow this, I deleted the entire solution and started again. Unfortunately, I reached exactly the same point and decided to read the instructions, where it was written that the same numbers can be in the same area. The moral here is - always read the competition instructions very carefully and mark important things in a different color. I managed to solve 11 sudokus, which gave me 3-4 places. Only Jan and Peter Hudak from Slovakia managed to collect more, who probably solved 12 sudokus. So Jan 98p, Peter 95, me 86, Hideaki Jo from Japan also 86, Kota 79, Jakub 69.

It was a round with 15 alternative sudoku variants that were somehow associated with Disney characters. The sudokus gave quite a few points compared to the sudokus of the previous round, the non-consecutive sudoku stood out, which gave 12 points (less than several of the previous round's ones). I started solving from the beginning and several times I reached a point where there was no solution anywhere to be seen. I admit that I had to try in several places and the other competitors confirmed the same, that these were not logically solvable sudokus. For the most part, of course, the solutions were beautiful. Then I reached the consecutive sudoku, which gave 6 points and started running out of nowhere. The entire sudoku had only one No. 1 and in some places signs that denoted consecutive numbers. Apparently the solution came about by trying to find a placement for all the No. 1s and 2s, but after a few tries I gave up and moved on - 6 points was not worth it. In the meantime, I did one 5-point puzzle, which probably didn't take much more than 2 minutes. Then I got to this non-consecutive sudoku, where I managed to find only one number and then after 5-10 minutes of analyzing and searching I didn't find a solution and unfortunately I had to skip the sudoku again and accept that the time had been wasted. After that, others said the same thing as me. The result was 53 points, which surprisingly gave me 5th place, with only Kota 69 and Hideaki 54 getting more from the closest competitors (in addition to Florian Kirch from Germany 62 and Mehmet Murat Sevim from Turkey 56 - who were no longer threats in this tournament). Jan 50 and Jakub 36.

This was the last individual round and there were 3 sudokus that were connected to each other at the corners. One 9x9 classic and one 7x7 special shape in each corner. The overlapping parts were 2x3 in size. Unfortunately, I managed to make one miscalculation during the solution and the solution in the top left corner was incorrect. Since I didn't have enough time to do it all over again, I decided to try to find the mistake. However, I couldn't find the mistake and took such a risk that I tried to do at least the classic one correctly. However, this was a relatively foolish hope that it would be correct, because it depended greatly on the top 7x7 sudoku. After this round, I had a feeling that I probably wouldn't make it into the top 8, but when I saw the results the next day, I was surprised - the 9x9 classic was correct and the result was 21 points (the 7x7, which gave 9 points, was only wrong). And what was even bigger surprise - I was in third place in the overall standings, which was a great starting point for the final. In this round, only Jakub 51 (30 a lot of bonus points) scored more than the main competition. Jan 21, Kota 0, Hideaki 0. The competitors behind the top five practically all scored over 40 points and came somewhat closer.