IPC Preview – Practice, Solving Tips, Links

Update: Fixed the typo in Pentomino Kakuro. New PDF uploaded. No other change.

Update: There is an erratum published on the IPC site that says the 2×2 restriction applies to Happy Dots too. Since the practice puzzle in the PDF still gives a nice practice for placing the dots and forming regions, and only uses 2×2 regions minimally, it stays the same in the PDF. We’re sorry for the inconvenience. 

If you’re having trouble with some puzzles, seeing/adding to the discussion in the comments might help. (This also serves as a spoiler alert for those who want to work on the puzzles without help)

Right, took a while, but we’re finally there. If you’re still not aware, the Indian Puzzle Championship will be held on 7th July. Here are our (me and Swaroop) best efforts, with the main goal being to try to help the newer participants.

This PDF features –

1. Practice puzzles for B1, B2, C, D, E2, F1, F2, G2, I1, I2, J1, J2, K1, K2, L1, L2, M2.

2. Beginner-level solving tips for all the puzzles in the set.

3. Solutions to all the puzzles in the set.

4.  Links to other practice material, pattern guides, and other technical tips.

Link to PDF – Practice

Enjoy!

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17 comments on “IPC Preview – Practice, Solving Tips, Links

      • Hey can u help me out with black and white puzzle.. I need some tips and tricks to do so…

      • Hey can u help me out with pentomino karkuro puzzle.. i can find out from where to start and how to start… please do help so..

      • Hi. have you scrolled down to the tips yet in the PDF? I’m asking because I particularly stressed on how to start the Kakuro in there. Maybe you’ve missed it. Just remember that sums can never be “blocked” in a Kakuro. E.g. a 42 clue outside the grid means there will be no Pentomino piece for at least 7 cells across or down that it’s pointing at (at least 1 cell for 3, and so on). Do check out the Tips in the PDF right after the puzzles though 🙂

      • I have tried your method by blocking all the cells but then i don get an idea to pllace which pentomino at whch place.. and evn in black and white puzzle i cudnt find any clue further…plz do help

      • Ok, well, in Pentomino, you need to remember that its not just blocking cells from the outside sums, but also knowing the limitations while placing pentominos. You can actually know which way to rotate it just by looking at it. For one thing, remember that in a normal Kakuro, you always have the clues this way – (Down-sum\Across-Sum), so eliminate possibilities with the forward slash (“/”). Now look at the Z shape. It can only be rotated 2 ways, going by the previous sentence, and in one of those ways, the (4\9) will end up being blocked by the cell beside it. So it can only be placed with the (9\4) at the top right and the (13\-) at the bottom left.

        So, I guess you have R1C1, R1C2, R2C1, R2C2, R3C1, R4C1, R4C2, all blocked from being a Pentomino piece, and also 3 cells from the 21 sum at the top. The main trick is, if R3C2 is also blocked, then you have 2 groups of 4 for the 2 11 sums at the top, out of which only 3 and 5 can remain for the 14 sum, and another 3 and 5 for the 12 sum, which means they both have to be extended. But because of the 21 sum, the 14 can only be extended 3 cells and the cell after that is a Pentomino piece. If you join up the Pentomino pieces around this area now (taking the 2 formed to the right of the 3 sums as well), then you will get an upside down P, and also using the no touching rule, the 12 sum will get extended for 5 cells and thats your contradiction. So, R3C2 cannot be blocked, and is a Pentomino piece. That should give you a 2 in R2C2 using the 11 sum and the 3 sum, and also a 9 in R1C2, 1 in R2C1. That should get you started.

        Let me know if you want this in more detail, if not, then we can continue to the Black and White puzzles.

      • ya i got it…thanx a lot for u help.. i can undrstnd it well now..ans wht abt black and white and wvn black and grey one…

      • Black and White Loop – There’s many possible ways to start here. Lets take the right bottom corner for example. The loop strand coming from R10C10 to R9C10, if it turns left, and meets the black, it forms a “corner” in R8C10, which means the 2 whites in R7C10 and R8C9 will have to connect by a turn, which is not possible. So extend the strand from R9C10 to R8C10 instead of turning. The strand from R10C9 can’t turn either, but this is more direct, as it hits a white upon turning. So, extend that strand to 10C8. Now we have 3 new paths to follow – A “corner” forms in R9C9, which means R9C8 and R8C9 have to be connected through it. And, the strand from R10C10 which is now in R8C10 cannot turn because there’s a white on the turn, so has to go straight, and the strand from R10C10 to R10C8 cannot go straight and has to turn because of the blacks there. Use these tricks throughout the puzzle, and you should solve it. Then, use these tricks for the Black White and Grey puzzle too, and only use the Greys when absolutely needed, and see how far you get. If you still need help, let me know 🙂

  1. One more tip you can add for Pentomino Kakuro is uniqueness Funda to solve it e.g. top left corner for first 3 there will be two blocks. So for the other 3 there should be only one block otherwise solution will be non unique.

    • True but its my personal opinion that I don’t think that’s a step that should be put out there as a tip, because its really a selective (for lack of a better word) logic to spot and can be used very rarely. Another point is that its unfair to the people who already downloaded the PDF if I change it now. However, good observation, maybe people reading the comments can see if it helps them.

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