24HPC in Japan, and a bit about JPC

On May 4-5, some Japanese puzzlers solved puzzles from 15th 24HPC in Joes' home. Almost two months have passed, but these days I have some time to review and solve the remaining puzzles,  so here are some notes about my experience and feeling. Scores can be seen here as a reference (I think you need to download to view properly).



Round 1
Lovely theme. My target that day was 900 points in each round, and I thought both of Magnets variants are low valued compared to the amount of work, thus I started from Japanese Sums and went backwards. After going back, I moved on to Magnets, but I broke it and I did not have enough time to retry.

I felt Compass has more chances to work well with other rules.


Round 2
I started from the highest. 25 minutes were left after smooth solve. My plan was not checking till the end, but taking rest after checking once. I used 5 minutes in this round, and it turned out to be error-free.


Round 3
Started from Four Colour Masyu and then Exclusive Mix, but sadly I made a mistake in the last cells of Masyu.

First one of Skyscrapers [Chaos] was harder than expected. Considering the point value, I feared to solve second one and solved Tents and Trees, which I saved for last, in the end of the round. But that Skyscrapers actually was very comfortable one. I regret having passed it.


Round 5
We solved all 14 rounds, but the Japanese round was the last round because some participants are authors/test solver. So next was Round 5.

This was my second choice for ignoring round,  and in fact I should have chosen this round. Targeting 900, I started from Voyage to France, but this was the start of the collapse. One more trouble was in DNA Sudoku. I thought the letters were only for "easier tracking", and believed the connected point was 5.

Second Tapa was my error. I like Spy Battleships type, by the way.


Round 6
My most disappointed round. Mainly because I broke Summons many times, and because I could not find how to solve Loopki. Changing a puzzle into another type is my favorite, but I even broke it! And I feel Loopkis are great, too. I had checked the patterns, but did not understand it enough.

I regret not solving Compass, too. Yes, I could not find the entrance at first glance, but giving up good puzzle is my sadness.


Round 7
I could not finish second Star Battles, and the others are my errors.

In my feeling, points distribution is inappropriate in many places, and hard puzzles tend to be try&error.


Round 8
75 minutes for solving, 5 minutes for checking, 20 minutes for the rest; same as Round 2. The difference is that I made errors.

The puzzles are stable. I am curious about the unfamiliar grid size.

Slash Pack can be solved so easily when uniqueness are used. It is too much valued in this sense.


Round 9
I wanted to solve at least one Battleships in Hexagon, but they were impossible. I have not solved them yet. Frankly, this type breaks the round. IFF rule should be inappropriate here.

Second Thermometer-Ying Yand had no solution. It was easy to find, so during the round we discussed and decided to treat everyone as correct. Scrabble had multiple solutions (probably 3 patterns were submitted at that time).


Round 10
My ignoring round. Arrow Maze was marked incorrect because of ambiguity, but I felt it is solvable. Even if this was ok, this is still my least raw score, but I made a bad choice in the sense of contest points.

They are much amount of try&error and were a bit too hard. In Arrows, I prefer second one for the same reason.


Round 11
Same experience as Round 2 or 8. Surprisingly, every time when I saw my watch, it showed "1:15". The puzzles were comfortable and good for the rest. It had been better if I had used symmetry in first Triple Block.


Round 12
15 minutes were left. I began feeling tired, and the puzzles themselves were harder than in Round 2. I solved intuitively in Fillominoes.

I started from high pointers again. Consistent theme through two rounds.


Round 13
Wonderful theme! I enjoyed Pentominoes thanks to this theme. And here is my joking error in Scrabble:

In Japanese pronunciation it can be B.... Our typical confusion is L/R, but B/V here.

Another error was in first Mastermind. It is so confusing to use a digit twice.

I felt first Group Sum Doppelblock is easier than second one. I am missing something with this type?


Round 14
Because of some troubles, I had little time for Dissection. I managed to solve two of them in the very last second. Satisfying spurt.

Stable Serkan round as usual.


Round 4
To be honest, this result was not expected. I am still wondering why. It is true that I am familiar with authors and puzzle types, but I think these are not enough to explain. What was critical?

I left 15 minutes for second and third of Honey Islands and Curve Data, and solved these four puzzles one by one. I finished in the last minutes. Considering authors, I do not recommend to solve these types earlier.

Here is a strange error:

Bodyless snake!

Second Battleships has cool logic.


Overall
We hold this event since last year (same days). I remember that last year I thought "I do not want to solve Latin squares, but nothing I can solve is left except these!" again and again. This year I do not hate these anymore, and I could enjoy more thanks to this improvement.

Next year, if puzzles are in public, we would like to use the same holidays again. We have many holidays in the first week of May, and this is called as "Golden Week".




Next, about JPC.

JPF has announced the schedule of JPC and JNPC;
JNPC: July 11 13:00-15:00
JPC:   July 25 13:00-15:30
Both are in JST.

Timings are fixed, but international participants are welcome of course. I expect English instructions from organizers.

Systems of WPC and WSC team selection are:
1. Top 4 players are in A-team.
2. Next 3s are in B-team.
3. If these 7s include at least one newcomer, next one is in B-team. If not, top newcomer is in B-team.
No one is seeded.

JPC is the event I can find least meaning for win. I still remember my disappointment two years ago. Ko is not in organizing team this year, and the selection is tough as usual. At least I have the right to go to Sofia because of Puzzle GP, but.... Let's see what will happen.

Two contests are held in different days this year, so I will join in JNPC, too. My fear is that I accidentally get A-team seat. I think the tendency of JNPC is different from that of WSC or other contests; it is rather puzzlish. With my position and eagerness about Sudoku, it is enough for me to compete unofficially in WSC.


By the way, about "puzzlish Sudoku" in conclusion. I do not think only the combinations with typical puzzle type are puzzlish. I do not have enough words to explain the difference well, but a typical example is Killer Sudoku; Japanese authors tend to make this type without fully using cages, and I am comfortable with this just as a puzzler.

It seems that some sudokers do not want a part of puzzlish Sudoku. But I do not know where is the boundary. I talked with Kota about this, and agreed that the boundary should be determined. I fear that I cannot meet good puzzles due to the ambiguity today. If you say these types do not fit Sudoku tests, they can appear in puzzle tests. Sudoku is a kind of puzzle, anyway.

JdZdC 2014

Around a year ago, a puzzle competition named “JdZdC” was held in Japan. The puzzles are published recently; see here. I made Round 4 for this. I used new puzzle types themed by “warp” (I wonder if this usage of the word is Japanese style; we mainly use this SF meaning), and here I will write about this theme.

In Nikoli's main quarterly magazines, there is a place to invent new puzzle types. In 2012, "Warp Hole" appeared in this article;

Rules: Place two circles (warp hole) into every region. From each arrow, a spirit starts in that direction. When it reaches to a circle, it goes to the other circle of the same region, and restarts to the same direction. The numbers beside arrows show how many times warp holes are used by that spirit. Every warp hole must be used at least once.

and an example:

In fact, I have never seen the last part of the rules is used, and such ones are a bit harder, of course;

I liked this type, especially the concept of warp, but it soon disappeared. I believed this concept can be used more in puzzle, and my round in JdZdC was my answer to this.

English instruction is prepared here. Note that this round was so hard because of my misjudgment. I asked gorogoro for test solving, and thankfully he also made some good puzzles. So they are included in bonus puzzles. Credits are not written explicitly, but obvious from the figures.

Japanese are used in some gorogoro's puzzles. It is hard to explain all, but I especially want to explain one of them. See page 2 of the bonus puzzles. Target word in the 2nd puzzle is based on a tongue twister, which is related to peach. And mirrors in the grid also represents peach. This is deformed representation, but common in Japan.

This offline competition will be held again in March. I hope we can publish the puzzles earlier this year.

WPC 2014

Many days have passed since WPC. I didn't have enough time to recall, but now it's time for me to review briefly.


WSC
Well, I don't remember so much about WSC. Apparently I didn't concentrate on it. I wish I could enjoy sudokus more.... But I was able to practice finishing in the last individual round, this should be good. And congratulations, Kota!


Q&A and Open meeting
I was a bit tired after the sightseeing (it was enjoyable, of course!). It is still difficult for me to understand the whole English. Almost no problem in Q&A, but I needed to rely on Yuhei many times in open meeting. I should improve my skill.

Talking about Q&A, I usually paint all black cells in Yajilin. And what I knew about Area 51 was only concerning baseball. The pronunciation of some Japanese puzzle names was surprising for us.


Round 1
Before the start, I noticed that Palmer was behind me and Florian was in the front left. How should this have been decided?

I finished with 8min left and began checking, then I found a mistake on Striped Snake. I could not correct it soon, and I managed to submit with 1min left. But it was still incorrect. I overlooked the wrong place while tweaking.

The last one uses some Japanese puzzle names. We thought we had an advantage, but in fact, we don't know "KURODOKU". What we know is "KURODOKO". Dangerous.


Round 2
No problem, of course. I used a minute for checking. I needed to shout because I feared to be ignored, but maybe no need?

My submit time was strangely recorded as 16:56 at first, so I had to protest to get 15 points.


Round 3
I had to erase the 2nd Tapa, Tents, Battleships and Hashi again and again. Kota told me a logical path of Tents, and that was interesting.


Round 4
Hard round for me. After I finished Kropki, I went back from the last. So I left No.12-14, and the 2nd Mathrax was wrong with 3 cells.


Round 5
I could not figure out the rule of Kakuro-like one soon, so I left the 2nd one. And both of word puzzles were wrong with 1 cell or 2 cells. I should accept sincerely that I am not a native alphabet user.

All rules seem reasonable to me.


Round 6
I left 3min. Yeah, I finished this round. But I made so many 3 mistakes. Shikaku has only ambiguity problem,  but the 2nd Unequal Length Maze was completely wrong, and I was laughed at by teammates because of the mistake in the 2nd Slitherlink.

Wow.

I'm wondering how to solve No Four in a Row logically. In this type, try&error is just boring.


Round 7
We had a bad performance. Hideaki was exhausted at that time. I thank Kota for helping my intuition in the 3rd one, but I feel we could be more intuitive.


Puzzle GP Final
Before the audience gather, I checked whether I can distinguish the score table. I tried better glasses, but I could not (I have bad eyesight), so what I could learn from the table during the final was only the color.

I was caught by the first Crisscross (word puzzle again!). This was the same situation with the other Japanese, but the difference is that this was my first playoff. I was too hurried and made 4 errors (Easy as x2, Spiral Galaxies, Kakuro) from minor to major. And Count Number was treated as wrong at first. I checked my solution, but I could not find any mistake, so I said to Helen, "What's wrong?" But of course she could not answer. So I connected 1 from N in each region, then she dubiously looked at my paper. Without my submission, she brought it to Wei-Hwa, and I went ahead without waiting a minute. Later, I knew that my poor numbers caused her misreading. Sorry Helen!

When I looked at the scoreboard after the final, I learned that I didn't need to be hurry. I often forget this important thing and result in many errors, like in Round 6. I learned the same thing again.


Round 8
I erased the 3rd Flowerbeds, the 2nd Vegetable Plots and the 2nd Snail Skyscrapers many times. I managed to solve the Flowerbeds but it was still wrong. However, my most regret is that I didn't even try to solve the last one.


Round 9
Caught by the first one, but small problem as a result. Checked a minute again, then shouted again. Starting point of Hiking path is tricky and interesting.

In spite of the result, I have never thought that loop puzzles are my best. On the contrary, I believed that I 'm bad at Slitherlink for example, but maybe this is because I'm in Japan.

Combination of Cave and other types was a problem for me, because Cave is the only puzzle I usually paint inside the loop. After the Beginner's Contest, I'm thinking about changing my style.


Round 10
Kakuro and Magnets were left. Happy if the last quarter of Kakuro were completed, but I wasted much time in Pentominos, one of the easiest. I had little time for checking, so no mistake is enough here.


Round 11
Why did I top this round?


Round 12
I heard that Toroidal Numberlink was the hardest, but luckily, no problem for me. I was caught by the 2nd Every Third One, which I left for last, but still I could finish.


Round 13
Larger Tapa was the hardest for me. I used 10+min for T sets in the LMI practice test, so I solved this in the end. But no problem here.

I wonder how to solve this round within 30min....


Round 14
Masyu&Yin Yang was assigned to me. I think this was because I am accustomed to a special strategy of Yin Yang (I solved both in Beijing with the same reason, too). After this, I went to LITS&Star Battle, and then helped Kota with the highest Cave. But maybe I should have changed this order. Yuki's Numberlink solving within 90sec was impressive.


Night session
Great one! I think Ko would have liked it if he had been there. I will probably show papers to him.

I broke poker puzzle twice and left it to Takuya. Sorry, but I was tired.


Round 15
I'm so sorry for my knight step error.

I feel we should prepare much more for team rounds. It is obvious from the result (including WSC) that Japan is bad in team rounds, but this is natural considering we don't prepare at all.


Playoffs
With the result of GP final, I changed myself not to do the same thing again. This was achieved, but not enough to complete the race. I had bad experience in almost all puzzles, even in Area 51 (Nurikabe might have been the only exception). Just the result of my weakness. And I should have searched this site before.

Congratulations to all the podiums, especially to Palmer on his great performance in the final. I still have much to learn from my idol in my early LMI days.

My target this year was to be the youngest champion (as long as my knowledge is correct). One dream has broken, but I believe I can be much better. I will try for my next target.

...a little bit bitter to know that I was the only Japanese who won nothing in London, though.

By the way, how can I solve the remaining Masyu and the puzzles in previous rounds?


Others
Thanks for all who bought Toketa. I hope you enjoy it. And there is a questionnaire here. Please tell us your opinion for future Toketa.

I learned that the order of my first name&family name can be misunderstood. When I registered in LMI, the order was not designated, so I used the Japanese order, but I should have used capital letters for the family name like Yuta.

Anyway, I had a wonderful week in London. I could feel to be treated as a player, a large difference from last year. I should start from JPC again next year. I know that I would not have been in London only if Yuta could have participated in JPC. Hard qualification, but I will do my best to go to Bulgaria.

GP 2014

All GP series ended last week. Here I write about two things.

First, about examples in the instructions. What are the roles of examples? Of course they should tell us how its rules work, but sometimes I saw examples which don’t need all rules to solve, and had trouble with contest puzzles. As I’m an accustomed solver, I need to learn only the rules which I see for the first time, but for beginners, the risk of wrong rule interpretation will increase if bad examples are provided.

Another role of examples is to tell how contest puzzles will be. PGP Round 2 is a good example for this. In this round we can learn from the instruction that grid shape is not rectangular, and we may even predict that all grids are the same shape. Moreover, proper examples can give more information to the solvers, but this power of examples seems not recognized enough. Though non-rectangular example makes us wonder if the contest puzzle is also non-rectangular, we saw such bad examples many times. And one more point: some examples are used again and again, but the sources of them are not mentioned. Example puzzles should also be thought highly of.

The next is about the difficulty of the GP series. It is said here that “The puzzles in the Grand Prix will be designed for all the players with different solving skills, for beginners as well as for the best world players.”. The difficulty I expected from the sentence is that of PGP Round6, so I felt the other PGP contests are too hard. I introduced GP to my puzzle friends who are not familiar with contests, but sadly, one of them even asked to me that “is it really for beginners?”. Satisfying both top solvers and beginners in the same contest is a hard job. If we want to do so, I think we should allow some differences between GP and other contests, and maybe the differences of results as a consequence, too.

By the way, I asked my friends the order they solve in the contests. They start from the types they know well: mostly from nikoli puzzles (this is natural because they are Japanese, though solving steps are far from that of nikoli’s puzzles.) and next, try for the types they think they can solve. They tend to challenge the types they have seen in the earlier GP series, so using the same types continuously may be good in GP. And they also look at the points tables when choosing which to solve, so proper point distributions “for beginners” is important. I felt some puzzles had improper points, and others were valued only from the seasoner’s side; sometimes this makes big trouble for beginners. We should keep in mind that difficulty for top solvers is far from that for beginners.

So I think GP series should be controlled more by the organizers. I want to see appropriate difficulty and point tables. And I also want to ask the organizers for not changing difficulty and maximal points in the series. I think I had an advantage from lower points in the last round of PGP, and my 2nd position in the final result is unfair. But anyway, I can enjoy the final as a solver.