Non-bookish fun

Saturday, March 8, 2008

My honey brought a Southwest Airlines in-flight magazine for me to read, brought back from his latest trip. I got hooked with a puzzle called "Shinro," which reminds me of Sudoku, but more obscure and confusing. You can see the original puzzle here. Tricky, isn't it? I became obsessed with solving it. (Sadly, "obsessed" is not too strong of a word.)

At first I googled the puzzle, trying to find the methodology for solving it, but there was nothing out there. We were beginning to think it was another prank by Southwest, until I found posts like this, asking where to find more puzzles. So once I solved it, I decided to post how I got there, to help other obsessive puzzlers like myself. Enjoy! (And if you used this and found it helpful, please leave a comment.)

First, I redrew the grid larger, using a pencil with a eraser.

Then, add tick marks to show every square an arrow is pointing to. Some squares have more than one tick mark.

Here's where the fun begins. Remember, holes don't necessarily have an arrow pointing to them. So looking at the last column on the right, there are two tick marks in that column, and there are two holes in that column, but that doesn't mean that those squares are where the holes are.

Here is an example of the logic I used to solve this one. Looking at the row the pencil is pointing to, the row has only 1 hole, and it must be to the right of the arrow. Therefore the circled tick marks aren't for that hole, so I erased them.

Looking to the arrow above, that particular arrow is only pointing to one square. Therefore there that's where the hole is.

After an arrow can point to no other holes, X through it. When a column or row is complete, I check it. I erase the tic marks when they no longer indicate a hole.

Continue until the arrows can point to no other squares (Eight holes so far.) You still have unmarked holes somewhere in the puzzle. At this point, I decided to put a line through finished columns and rows to make it easier to see where the holes are.

From here, you can see there is only one spot in the top row where the third hole can be.

Keep going, and you solved the puzzle! Isn't that fun?

PS: Thanks for the math and logic classes, Mom and Dad! Education is never wasted, even if (or maybe especially if) it's used just for fun.


Leslie said...

yay! this was extremely helpful for many reasons! Thank-You!

Anonymous said...

That process works great, but if you see puzzle 3 on

it does not solve the entire puzzle. Any ideas on how to fix this, rather than a random guess?


Anonymous said...

I mean puzzle 2, it takes you to a point where you have to start guessing.

Anonymous said...

nvmd all looks good mate.

Rachel said...

Good, I'm glad you got it. Often, redrawing and starting oved helps.