Wednesday, November 11, 2015

WPC 2015

I managed to have time to solve all individual puzzles I could not solve in Sofia. Here is my review of this year.

I competed officially this year. Normally, in Sudoku contest, I do not think so much about my score, and just solve in the order. But my task in Sofia was acting in place of Hideaki. So I needed to consider my solving order, and concentrate more. Thanks to these efforts, I remember my experience better than last year. I will write about WSC, too.

When I was looking for my seat, I noticed that JPN-A was next to EST-A, and even FRA-A and CZE-A were in the near places. It became a funny area.

Round 1
Left: #10-12
My weakness in Sudoku comes mostly from Classics. Especially, I cannot solve the hardest side well, so just started from easy ones. Safe strategy was enough for me. All puzzles were of reasonable difficulty as a result.

Round 2
Left: Cube, XV, Clone, Diagonal, Classic x2
Another Classic weakness is the lack of speed. This means cheap puzzles can be ineffective, and conversely, if I believe that I would be able to complete high puzzle, it deserves to try. So I started from 1234. It took 12-13mins, but still I feel it was good choice. And it was the enjoyable puzzle in itself.

Round 3
Left: Inner Frame, Max Triplet, Classic #2
This time I feared Max Triplet (and this seems correct), so solved in the order. Cheap Classic is good for the last minutes.

Round 4
Due to wrong deduction, I broke it once, but luckily, I could correct it without erasing so much.

This year, in the one-puzzle rounds, time bonus was reduced. This seems reasonable considering the risk of this structure.

Round 5
Left: Greater-than Consecutive, Kropki, Even Sandwich, Next to 9, Mathrax, Classic x2
Bad result, or I just returned to my usual. Everything was not smooth. Maybe I felt tired after lunch. I like Greater-than Consecutive, and Kropki was instructive for me.

Round 6
Left: Toroidal, Classic x2
Ignored Tridoku at first, and returned to it because the remaining time was not enough for a Classic. Parquet was cool.

I feel "Overlapping Sudoku" is an abuse of the word; it is just a Latin square type without any regional rule. I do not care about the appearance of such types in WSC.

Round 7
In my team, we agreed that ranking in the team is 1. Kota, 2. Takuya, 3. Keisui, and 4. me (same as the order in JNPC this year). And the seats were set as 1->3->2->4.

I solved Extra region quite well. I solved it even faster than Kota. And then I was waiting for Takuya.... He broke it, and needed to restart. I was just sitting for a while, and finally it was relayed. And I broke Irregular! Not enough time for repairing, so I sent it to Kota and he managed to solve the following Classic.

After the round, I learned that the puzzles were actually the same, only numbers were exchanged.

Round 8
In the morning, I heard that I was in the good position for playoff. I had never expected such a chance, and to be honest, it was the first time for me to think about that borderline.

So I decided to start from Twin Region, and solve in the descending order of points. This strategy worked quite well as a result.

In Twin Region, converse sequence was allowed, but it is impossible in fact. This was helpful.

Round 9
I made many errors. Somehow I corrected them all and finished. This was of importance.

I hope gray cells are painted in lighter color.

Round 11
Central part was broken, and Kota repaired it. While repairing, the other 3 were checking, and found that I had made 2 errors inside 6x6. Ah.

And I was in the 8th place. Anyone expected? Kota said that this year there were more puzzlish Suodku. This seems right. I do not mean only newer types were puzzlish. Common types were also on the puzzlish side. This is why I was comfortable, I think.

Also, I made no wrong submission in WSC. I was lucky. I do not expect better results in the future, and even B-team is okay next year. I just want to solve puzzles in WSC.

I am happy with my team result. I felt I achieved my task.

Kota: Arrow in 4th - He decided to choose Arrow because of SGP Final.
Tiit: Diagonal in 1st
Jakub: Even Sandwich in 3rd - No problem for Kota, as he agreed later.
Bastien and Seung-Jae: Irregular in 2nd and Killer in 3rd - I forget who chose which.
Michael: Greater-than Consecutive in 1st - It was impressive and I remember it.
Cheran: Extra Region in 2nd
Prasanna and I: Surprise in 3rd - We had same points, surprisingly, and chose the puzzle together. Surprise was attractive, and one more reason for recommending it was to reduce the risk in the final, as a teammate of Kota.
Kota: Inner Frame (remaining) in 2nd
And Surprise was revealed as Non-consecutive.

This was the bonus stage for me, just for amusement. I made fool step in Extra Region (it was Windoku in fact), and while restarting, I was even wondering "why I am here?" Good experience, anyway. Prasanna won the round, so he should have made a good puzzle selection. Later I solved Surprise and it was actually good surprise.

Congratulations on Kota for another title.

At that time, WPC instruction was still not published. I noticed it during sightseeing. If I could have read it beforehand, I had been to the museum.

PGP Final
Killed by the first one again, killed by the word puzzle again. It was too large and tricky for me to grasp. After that I did as usual, but I made a wrong deduction in the Cave and made an error. First error in Sofia. Still, I managed to reach the last puzzle (for the first time in playoff), a bit later than Matus. And Find the Pair benefited me. 3rd place is much better than nothing, like last year.

After the final, I noticed that there were puzzle names on the result table. Were they published before to start? I was always predicting 2 types (except Neighbors).

By the way, after SGP Final, Kota recommended me to prepare a binder because the table mat was uncomfortable. Good advice.

Like WSC, JPN-A was next to USA-A, and NED-A was near. It was attractive, but Kota chose that seat, so I chose near Ulrich this year.

Round 1
A strange bag was on the table. Puzzles were not normal, as expected. I solved in random order and checked carefully after solving each puzzle. Tapa was 2nd for me, and I left it for the last when I noticed it was not unique. I had more than 20 mins when I returned to Tapa. The problem was, if Tapa was valid, another error means no partial credit. So I checked all puzzles again, and fixed an ambiguous place in Fillomino (in dividing puzzle, dashed line is much better, by the way). That was all.

Round 2
Left: Clouds x2, Triangular Minesweeper (2nd)
I broke Coral once, but I did not notice missing 1 in second solve. I was lucky.

Clouds and Triangular Minesweeper was left for the last, and I did not have enough time. One more minute was enough for 2nd Clouds, though.

Round 3
Left: Chaos(2nd), Encrypted Square x2, Kropki (2nd), 2D Magic
Error: Doppelblock (1st)
The error is because I erased too much while solving 2nd one.

I solved in the order, and after I broke hard Chaos, I moved on to random solving.

I showed my weakness - same as in London. I could not believe Ulrich's finish at first. Long way to reach that level.

Round 4
Left: Worms (2nd), Striped Snake (2nd)
The result seems good, but I was not so comfortable. For example, I broke Cave.... Again!? And Worms (1st) was solved in the last seconds. Just lucky.

Round 5
Solved: Japanese Railways x2, Easy as Tapa (1st), Snake in the Naval Forest
After Japanese Railways, I went to Easy as Tapa, but it did not work at that time. Then I started Snake, broke, erased, and broke again. This was in the must-solve list for me, so I was still thinking about it. And there was the announce. I was forced to restart with that change. After that, I was hurried with my bad performance, and broke Easy as Tripod/ABCD123 twice each. At last I returned to small Tapa. This time it went well.

The puzzles themselves are pretty good. And I know that I should have kept my pace regardless of the error.

Round 6
Great construction. When I got ready to claim, I heard Ulrich's voice. Did not notice Zoltan at that time.

und 7

Tapa by Kota, Fruit Basket by Ko, Akari by Maho, and Pentomino Areas by me. Ko completed faster, as planned, and he joined in Pentomino because the other 2 said they can solve by their own within the time limit. I did not make much progress at that time (around 10-20%?). A bit later, I started to help Akari for secure. After Tapa and Akari were solved, we started to paint (by the way, some of us broke crayon - I hope better tool). After painting, we gave up Pentomino with the little remaining time, and moved on to checking. Sadly, an error in Akari was looked over - it was too large.

Pentomino was solved around 30-40%? in the end. It caused many wrong deductions. I have tried it again, and I suspect that it has many solutions.

Round 8
Left: Puzzle2 and 6
I skipped Puzzle 1 - I did not notice that letter cells must not be used. And skipped Puzzle 2 without any notice (or just thought "triangle to hexagon?"). Puzzle 3 and 4 went well, and Puzzle 5 also worked well, though I feared that maybe diagonal touch is allowed. Puzzle 6 was hard to figure out. At first, I thought that the arrows indicate multiples of 9. In this sense, 9 was not a good example. Then I returned to Puzzle 1, and understood the rule. One problem was that all blank areas are also used once in the example. And I retried Puzzle 6, noticed that it is not multiple but sum. I tried the 1st one with target number 9 and broke it, then noticed that target number can be changed. But no time to retry.

Round 9
Solved in the order, just left Snake for the last. Tapa was solved by intuition. I made some errors in Snake, but I managed to finish.

Round 10
Left: Scissors x2, Mars and Venus (2nd), Cards (2nd)
Error: Checkerboard (1st), normal error in the final step
At first I skipped 4 types above. Nearest Tetromino was by intuition, it worked strangely well. Checkerboard was the most uncomfortable type for me. I should have done the others. I saw Scissors/Mars and Venus for the first time, and both were interesting.

Round 11
Left: Encrypted Skyscrapers, Tetroscope x2, Puzzle Knight x2, Encrypted Square
Error: Different Neighbors (1st), 2 missing digits
Solved puzzles were almost done in order. I tried Puzzle Knight in the end, expecting some points, but it was in vain.

Round 12
Left: Coriolis, Unequal Star Battle
My order was Yajilin, Rectangles, Pentomino, Domino, Different Neighbors, Magnets, Hula-hoop and Kakuro. Kakuro was completed in the very last seconds. If I did not break Domino, maybe I could have solved one more, but it seemed impossible to finish.

Every time I see "hard" Yajilin, it just requires some deep assumption. A bit boring. I used the same tactics in Different Neighbors and Magnets during the competition.

Round 13
I was the faster in my team, though not smooth, and helped Kota because he had broken his puzzle and restarted. Before we completed it, the other 2 finished theirs and began the final puzzle. Later we joined in it, and we alternately checked the small ones. I also checked one, but I feel I should have concentrated on the large one. I contributed little on it. It broke in the last steps, and we could not repair. About 5 pieces were swapped, as a result.

Round 14
Minesweeper and Tents by Maho, Arrows and Snake by Ko, Sudoku and Kakuro by (of course) Kota, and Different Neighbors and Slitherlink by me.

All clues in Slitherlink were revealed soon, and I solved it at first (in fact, it was wrong, and later I was asked to repair it - how stupid I was to make mistake in such an easy puzzle!). Next, I finished Different Neighbors without a clue, and helped Tents and Mineseeper. Both had enough clues then. The main problem was that we broke Arrows, and it affected on other puzzles. At that time, puzzle distribution was, Arrows by Ko, Sudoku by Kota, Kakuro by me and Snake by Maho. I had little progress until some clues were filled. And even after all clues were revealed, it did not work. Only Kakuro was remaining. It was because of a wrong clue which was filled in during previous wrong deductions. I could not find it. From the puzzle design, it was hard to make notes, hard to find errors. It was preferable to use light gray in clue cells, not black as usual.

Palmer was in 3rd place, so I decided not to choose Tapa, for example, because he would choose that type. Playoff structure in these two years is good in that it assures certain ranking even if falling down, like me in London. But I think puzzle choice can be affected by the set of members in that round, which may reduce the advantage of preliminary rounds.

When I was sitting alone, Bram and Zoltan came and I heard that puzzle list had published:
2D Magic
Coral Maximum
Different Neighbors
Dotted Snake
Magic Summer
Pent It Black
Surprise Puzzle

Bram predicted that the number of puzzles would be 3/5/7, like in London. That sounds right, and then finalists would choose 3/2/2 each. I had no reason to choose Latin types. I hated Cave because I had broken that type twice in Sofia. I also avoided Polygraph because I felt it has similar aspects with Cave. And Surprise seemed a passive choice. I wanted to solve Coral, but I thought that Palmer would choose it if he can select 2 types. Thus, my first choice was Pent It Black at that time.

At the beginning of the selection, we were told that the number of puzzles were 3/4/5 in each round. It seemed that I can still choose 2, but only 1 for Palmer.

Ulrich: Kakuro in 4th - It seemed reasonable.
Me: Coral in 5th - I feared Palmer would not choose it. He told that it was actually his first choice. I felt I made a bad decision, and...
Palmer: 2D Magic in 1st - What?! I had not expected that choice, and my previous selection got worse. Also, I had not looked at this type in the preliminary round.
Kota: Rollercoaster in 1st - Quite reasonable.
Bram: Pent It Black in 3rd
Ko: Hexaislands in 2nd
Zoltan, Yanzhe, Nikola: Polygraph in 1st, Kropki in 2nd, Magic Summer in 3rd - I forget who chose which.
Ulrich: Chaos in 2nd - Again reasonable.
Me: Different Neighbors in 3rd - Because basically I feel comfortable with this type. Risky choice, though.
Kota: Fuzuli in 4th - Easy to predict.

Then I was waiting for my turn. 2nd Round was surprising. The reason why I did not choose Hexaislands was that I thought it would be easy and make little difference. Later I solved it, and it took an hour. I do not think this "type" does not suit playoff, but I believe "that puzzle" was too hard for playoff. I heard that Surprise was instructionless, and I think this "type" would not match playoff. Anyway, I was relaxed looking at the situation.

And the final started. See also the scoreboard by Takuya.

While waiting, I was counting time in mind, and my 2:51 counting was quite accurate.

2D Magic had good theme. 1-9 appeared once each, in order. I just kept in mind not to forget 0. I made many small errors, but every time I corrected them soon.

Next was Chaos. I feared this, but it went smoothly after a breakpoint.

Different Neighbors had good logic, which I had searched for in some puzzles but never worked. I was a bit lucky.

And Kakuro.... At least I have some experience as a Japanese. In Japan, Kakuro is also called as Sum Cross. This represents the difference of publishers, but it also shows the difference of logic. Kakuro in the final was rather Sum Cross, where addition of some rows/columns works effectively. I was lucky again, to solve this quite smoothly. And the air moved when I submitted this. I noticed something happened, probably I overtook Ulrich.

The last one was Coral. At my first glance, I cursed my selection - it seemed no start point. Actually, there was a place to start, but I made an error in the last steps. Worst error in the final. I needed to restart and lost a minute, but it was still enough. When I submitted, the air moved again, but I thought maybe I made a mistake, and even prepared for that case. More than a minute had passed, but there was no return, so I asked Vladimir, my marker, and then I knew I won. I did not look at the scoreboard until then.

Thank you everyone concerned, especially to Yuta and Kota, who invited me to LMI in 2011. My puzzle world was small then, just knew Nikoli. My first contest, Fillomino Filla, was wonderful, and impression at that time was why I could endure no-championship period in 2011-2012. I hope I will be able to return something to this community.

Still, I understand that I just won the playoff. It seems so hard to perform like Ulrich in preliminary rounds. Long way to go, but I will just keep enjoying.


  1. Thanks for this, great read. And congratulations again! Looks like you were fastest on all play-off puzzles except for the the 2D magic, that's pretty convincing.

    1. Thank you, rob. Playoff result is accumulation of many luckies.

  2. Congrats Endo! Great to see you peak in the playoffs this year after your disappointing show during last year's :-)

    1. Thank you Rohan. That is what I improved from last year.