Archive for the ‘Solving Tips and Tricks’ Category:

Ask Dr. Sudoku #9 – No Time to Close the Loop

Ninth in a series with puzzle solving tips. This time with advice on Slitherlink and loop puzzles in general.

Even if you had a good time on the TIME Slitherlink, the following walk-through might offer you some new tips — besides just memorizing Slitherlink patterns — to get better at loop puzzles.


Ask Dr. Sudoku #8 – No Subbing

Eighth in a series with puzzle solving tips. This time with advice on battleships puzzles, particularly missing clues and subs.

Solving Battleships is an odd experience for me. I think I want to enjoy them, but I’m not sure I ever really do very much. See, they were the first logic puzzle type I ever grew to love. But that means they also became the first logic puzzle type to bore me, and I’ve now been in the “bore me” stage for over half my life. And there is so much sameness in the Battleships you can find in the world right now. ~99% are randomly generated, ~99% give all of the outside clues which limits the challenge, ~99% solve by placing the largest ship(s) in the only possible spots and being good at bookkeeping of seas afterwards. As a member of the puzzling 1%, I am looking for something more. This week I tried to vary the formula a bit to make some more interesting — or at least different — puzzles.


Ask Dr. Sudoku #7 – Twisted Geometries

There is no Doctor’s Note this week.

Seventh in a series with puzzle solving tips. This time with advice on exploring unusual puzzle geometries such as the Saturday Sudo-Kurve.

When you’ve solved enough 3d Sudoku or Sudo-Kurve puzzles or other unique geometries (as in Sudoku Masterpieces), you’ve probably recognized there are sometimes cells or sets of cells that are much more constrained than others in the construction. This Sudo-Kurve grid, which I used in Sudoku Cup 3 and only one other time since, has some secrets to observe before getting too deep into any puzzle.


Ask Dr. Sudoku #6 – How to Build a City

Sixth in a series with puzzle solving tips. This time with advice on both solving and constructing skyscrapers puzzles.

I’ve gotten a lot of requests for tips on how to construct puzzles. I don’t offer many online as I have a monthly column in GAMES magazine that covers this and I don’t like competing with myself for less money. But Mike Selinker and I have improved on that content recently in turning our columns into a book, Puzzlecraft: The Ultimate Guide on How to Construct Every Kind of Puzzle. Please check it out.

This week, I thought I would give some insights into how I made this puzzle. Since I often construct a puzzle by thinking in the same way that I would solve the puzzle, the images below will show you both how I made the grid (and when I needed to use certain clues) and also how solvers likely completed the grid (and when they needed to use certain clues).


Ask Dr. Sudoku #5 – On the Parity of Loops

Fifth in a series with puzzle solving tips. This time, with some advice on global constraints that arise in loop puzzles.

Some of you have asked why I don’t put “general tips” up before I post any puzzles. I find that learning how to solve puzzles is more interesting than reading how to do every single step. I won’t post a list of the top 20 Slitherlink patterns you should memorize, for example, on the rules and info page. Most of you would probably get more enjoyment figuring those out for yourself. But, after you’ve solved a challenge, I do like highlighting some of the things as constructor I tried to include, perhaps as a lesson for the future. This is what I will do this week with parity constraints for the Friday Masyu.


Ask Dr. Sudoku #4 – Spelunking 101

Fourth in a series with puzzle solving tips. This time, basic steps to get through Cave puzzles.

While I’ve already written a good description of solving Cave (Corral) puzzles for the USPC, I’ve never drawn up some of the steps for more visual solvers. This week I hope to fix that by highlighting one of the more fundamental logic steps behind these puzzles.


Ask Dr. Sudoku #3 – Boxed-Into that Star Battle?

Third in a series with puzzle solving tips. This time, a dissection of Saturday’s Star Battle.

Jack Bross left an excellent set of starting tips for Star Battle in Dr. Sudoku Prescribes #14 so if you are struggling with these puzzles, start there. The hard Saturday puzzle required some unusual group recognition which I thought deserved to be highlighted.