0 Introduction

Follow along with the YouTube video if you hate reading.

I'm going to be calling it Picross, which is essentially the same thing as Nonograms, but with Picross the final grid will end up looking like a picture so it's more fun. Picross is a logic number game, and like all logic games there is zero guesswork involved. If you ever find yourself marking off a square by guessing and hoping for the best, then stop! Re-evaluate.

1 What is Picross?

Picross is like a colouring puzzle but with logic. You fill in squares one-by-one on an empty grid to reveal a hidden picture. The numbers on the sides give you hints for which squares to colour in.

Example grid:

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The numbers are clues! 👆

2 What do the numbers mean?

The numbers tell you how many squares in a row (sequentially) should be filled in somewhere along the row or column.

Important: For example, the number "3" means "fill 3 squares sequentially together in a row."
The number "2" means "fill 2 squares together in a row" without any gaps.

If you see "3" on a row:

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You fill in 3 squares next to each other! ⬛⬛⬛

Do not add another square directly next to these because then the clue would've said "4" instead of "3".

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3 Reading ROWS (left to right)

The numbers on the LEFT side tell you about the ROWS (going across →)

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Each row follows its own number clue! ↔️

4 Reading COLUMNS (up and down)

The numbers on the TOP tell you about the COLUMNS (going down ↓)

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Each column follows the number above it! ↕️

5 Working Together

Together the numbers will mix, as they intersect with each other, so you will have to fill in the squares that works both with the ROWS and the COLUMNS simultaneously.

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6 Mid-Term Exam

Stop! Let's take this moment to see if you've understood the rules so far before we continue. Below is an interactive nonogram, try to complete it before moving on.

Hint It's always a good idea to start with the largest numbers on the board.

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7 But Where To Start...?

It's rare you'll be able to fill out an entire row or column straight away. Typically, you're going to find one or two spaces to fill, which will (logically) open up the rest of the puzzle.

Example: Given a "3" clue on a 5-square row

Where can 3 squares fit? Well, it can go here:

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OR

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OR

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Notice that in all of those examples above, the middle square is black in ALL three cases!

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This means that no matter where we start our sequence of 3, there is no sequence of 3 that can occur in this row without that middle square being filled in!

So we can SAFELY fill that square in! ✓

This use of finding the "common denominator" in rows and columns is vital in playing the long game of picross, so here's another example.

Example: A "4" on a 5-square row

Where can 4 squares fit?

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OR

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These are our only two options to fit 4 squares in this row. Notice that the middle 3 squares are black in BOTH cases. These squares will always be filled in regardless of how we position our squares.

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Again, we can SAFELY fill those in! ✓

8 Common Denominators

Although you might be able to work out the common squares in a small grid, such as the 3 and 4 in the examples above, it gets tricky to do it mentally on the larger boards. Therefore, we need a way of finding the common squares without stress.

Here's my sure-fire method:

Left Side Start at the very left side of the board and begin counting the squares, one by one, until you reach the end of the number (eg 4). Keep note of where this ends. One-two-three-FOUR:

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4!

Right Side Then do the exact same but starting from the right side. Count the squares, one by one, until you reach the end of the number. Keep note of where this ends. One-two-three-FOUR:

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4!

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💡 See how the left and right sides have met at the same point, and then crossed over? These are always going to be common squares and anything in between are also common squares!

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Will this work with all numbers? Yes, if there are any common squares between them. But of course there will be many cases where there are no common squares. That's why you fill in the board piece by piece. For example, this method wouldn't work with a "2".

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2!

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No common squares to be found here! We'd have to move on to something else in a real game.

Try the interactive example below, figure out the common squares using the above "Left then Right" method before moving on!

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9 Using the RED X

Remember how I said if a row says "3" then you shouldn't add a fourth square otherwise it would've said "4"? Well here's where your red X comes into play.

When you KNOW a square should stay empty, put a red X on it! This helps you keep track of which squares are possibly valid, and it is mandatory for figuring out the larger puzzles.

Example: If a row says "3" and you've already filled 3 squares using other clues...

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Mark the rest with X! You're done with that row! ✓

A red X from the column "0" here helps us solve the rest:

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10 What if there are TWO numbers?

! This is the very last piece of information to learn, and it's extremely important. You can't skip this.

If you see two or more numbers, eg. "1 3", in your rows or columns that means:

First, fill 1 square in correctly
Leave at least 1 empty space
Then, fill 3 squares together

The order of the clue numbers is very important, it always reads left to right, and for columns top to bottom.

A row of "2 3 6" means fill 2 squares, leave at least one blank, fill 3 squares, leave at least one blank, then fill 6 squares.

If you see "1 2" on a row:

1 2

⬛ (space) ⬛⬛ - See the gap? That's important!

But how can we possibly know where the right squares are for something like "1 2" on a 5x5 grid? Again, here's where common squares works for you:

Start with the number "1" and from the left it's "end point" is the very first square.

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1 2

Then try it from the right side, counting the "2" and blank square as well since we need to bypass these to reach the number "1".

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blank

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1 2

Womp womp, we have no common squares for this number so we move on.

Then we try the number 2. Now here it's interesting because we know we need at least one square filled and at least one blank square between them before using our number 2 so we count from the very left: one-blank-one-two, and that's the end of our marker:

1 2

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blank

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2!

Now we start from the right side, but we know the number 2 is the last number, so we don't have any "buffer" we just jump straight into the counting: one-two from the right to find the minimum end-point

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2!

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Well look at that! We have a single square which is a common square! This means no matter HOW you try to place "1 2" on the board, no matter how many spaces between them, this one square will always have to be filled.

If this was a real board we would move on from here because we have no other information that can help us so far.

💡 Tip: Groups of filled squares must always have at least one empty space between them!

11 Intermediate Puzzle

Let's put your skills to the test with this intermediate puzzle.

💡 Both the number "5" in the row AND the numbers "3 1" in the column are able to be filled in without any other knowledge from the other squares. Remember how you need a space between numbers? That "3 1" actually ends up being "5" squares of information!

✅ Start with big numbers they're easiest!
✅ Use the X mark squares you KNOW are empty (right click)
✅ Work back & forth between rows and columns
✅ Don't guess! Every square can be figured out with logic
✅ If you're stuck look at a different row or column

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If you need help, here is how I would solve this puzzle step by step:

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Step 1 of 8

Start with row 5 - it says "5"!

12 Intermediate #2 Puzzle

One more to really get going.

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