This page describes how to solve nonograms using simple and advanced techniques. There are also some tools specific to Nonograms Katana, which significantly help the user to faster and easily solve nonograms.

## Contents

## Black-and-White Nonograms

### Basic rules

- Numbers on the side (later clues, sometimes called number bars) represent how many squares you need to color (i.e. colored squares, later boxes) in that line.
- Between those boxes there must be at least one empty space (later cross).

### Techniques:

These techniques are explained on a 10x10 grid. A "square" is an empty space on the grid, which isn't marked yet. A "box" is a square colored black. A "cross" is a square which 100% isn't colored.

All techniques are considered as basic techniques, except for contradictions.

**Simple boxes**

This technique is used beside the border and beside crosses. This technique is also used to fill trivial lines. You put boxes where there's no other option to put them elsewhere. Example 1: You have a clue of 10. You fill that line. Example 2: You have a clue of 3-4 and a box on the 1st square. That box has to be a 3. So you put 2 more boxes on the 2nd and 3rd square. Example 3: You have a clue of 2 and 8 crosses in that row. There's only one option you can put the 2 in.

**Simple crosses**

You put crosses where the boxes cannot possibly be. Example 4: You have a clue of 3-1 and 2 boxes on the 4th and 9th square. Then you know that the right box is going to be 1 and the left box is going to be a part of 3. You put crosses on the right and left side of the right box. Then you look where the 3 can go and put crosses where it can't. So you put crosses on the 1st, 7th, 8th and 10th square.

**Overlapping**

If the sum of clues and spaces in between clues in a line (you can measure it with the "ruler tool") plus the largest number is greater than the line, you can use this technique. It's recommended to use this when you start a puzzle. Example 5: You have a clue of 8. There are only 3 options this 8 can be positioned. Where they overlap, there's a box. If you've noticed, you can only put the 8 on the left and on the right side and see where they overlap. Example 6: Be careful, if you have a clue of 4-3, that you don't put boxes where the 3 and 4 overlap. Only put boxes where the **same** numbers overlap.

Math for example 5: clues(8) + spaces between clues(0) + largest clue(8) = 16 > line(10). That means that every clue in this line which is larger that 6 (16 minus 10) can be overlapped. The 6 also represents how many squares you can color for the largest clue. The number 2 (line(10) - clues(8) + spaces between clues(0)) represents how many squares you need to mark empty for each clue.

Math for example 6: clues(4+ 3) + spaces between clues(1) + largest clue(4) = 12 > line(10). That means that every clue in this line which is larger that 2 (12 minus 10) can be overlapped. The 2 also represents how many squares you can color for the largest clue. The other 2 (line(10) - clues(4+3) - spaces between clues(1) = 2) represents how many squares you need to mark empty for each clue.

Note: The "ruler tool" measures the combined number of clues and spaces in between clues (this number is 4+3+1=8 in example 6). To draw arrows like in the examples above, you can choose either one out of four arrows in the User interface > mark > arrow - up, down, left or right (see image). When you tap in drag in one direction the game will automatically select you the right arrow (e.g., if you tap and drag to left, it will select the left arrow and the left arrow will be drawn).

**Spreading**

This technique is used when you have one or more boxes near the border or a cross. Then you can "spread" that box away from the border or cross depending on how big the clue is. Example 7: You have a clue of 5 and a box on the 2nd square. You can put boxes on the 3rd, 4th and 5th square, because the 5 can only go on one square to the left.

**Forcing**

When you already have some crosses in the line, you can try to fit (force) the clues in the line. Example 8: You have a clue of 1-3 and two crosses on the 6th and 8th square. The 3 cannot fit in the right corner, because of the cross on the 8th square and it cannot fit in between the 6th and the 8th square either. So you put crosses on the 7th, 9th and 10th square.

**Joining and splitting**

Self-explanatory. Example 9: You have a clue of 5 and 2 boxes on the 2nd and 4th square. Both boxes have to be parts of 5, so you put a box on the 3rd square. Example 10: You have a clue of 2-2 and two boxes on the 4th and 6th square. If you try to put a box on the 5th square, you get 3 boxes in a row, which wouldn't be correct. So the only solution is to put two boxes on the 3rd and 7th square.

**Contradictions**

Sometimes it happens that none of the above techniques will help you further. This is more of a guessing technique, so it's better to check every row and column before you start using this, to avoid any mistakes. Here is probably the time when you would use weapons, but if you don't want, this technique will help you. It's probably a good idea to check for correctness and lock the puzzle, because if you find out that the box you put in is wrong you can just discard changes.

You try to put one box ("guess" box) in and try to solve as much as you can with techniques above. Also remember where you have put the box. When you come across a contradiction, you know that the box you first put in (the "guess" box), is suppose to be a cross. If you don't come across any contradictions, that doesn't necessarily mean that it's correct, so it's better to guess boxes that have only 2 options (if there is space for 6 boxes and you have a clue of 5 for example), which means a 1 in 2 chance to be correct. A special case of this technique is **edge solving**. This is done on the last row or column of the puzzle. Example: A clue of 4 on the last row. You try to put this 4 in the right side and try to solve with the techniques above. If you come across a contradiction you put a cross in right corner and only there. Then you move one square to the left and do the same thing. You can also go from left to right. If you are lucky enough, you can "guess" where this 4 is. And sometimes you just get some crosses in the corners of the puzzles that might help you in some other way. This technique is more useful if there is a clue of 5 or more on the edge and there is another large number beside it.

## Colored Nonograms

### Colored Rules

- The numbers on the side (later clues) represent the order and length in which that line is colored.
- If the clue contains a color twice in a row there must be an empty space (later cross) between them.

They are usually easier to solve than black-and-white nonograms. Same techniques apply as for black-and-white nonograms. You can imagen them as multiple nonograms layered onto one each other.

**Focus on one color**

When there's a low amount of clues of a single color try to solve that color first.

**Focus on the border**

Look at the last clues of the last or the first row and then try to match it with that column.

**Use the default pallet**

Sometimes it can be hard to tell colors apart, because they looks so alike. Double tap on any color any choose the default color pallet as this pallet has colors which can be easily differentiated between.

**Noticing patterns**

When you solve a lot of nonograms you start noticing patterns. Most of the time they mean what you think they do, but be careful, **not always**. Example 1a (edge pattern): if you notice large numbers in number bars on the edges which get smaller to the middle, that usually means that the edge is color. Example 2a (diagonal pattern): if you notice a bunch one's or two's, that usually means diagonal pattern (check if the pattern goes this way "/" or that way "\").

## Tools

Tools can really improve your solving experience. Tools help you solve nonograms faster and easier.

**Line tool**: tap and drag to color squares in a straight line. Especially helpful when coloring long straight sections.

**Free hand tool**: tap and drag to color any sqaure your finger touches. Useful for coloring squares, which are easy guesses.

**Rectangle tool**: tap and drag from one corner of the desired area to the oposite corner to color squares in the shape of a rectangle. Useful for coloring large rectangles.

**Paint bucket**: tap on a box, square or cross to color the entire section. It colors every square that is touching (not diagonal touching) the box, square, cross or mark you have tapped. Very useful for coloring large (irregularly shaped) sections of a nonogram, which you already know the outline of (the outline has to be colored first with a different tool). Be careful, you have to fully close the outline, or the tool will color some unwanted squares.

**Color picker**: tap on a box, square, cross or mark to select a color, empty square, cross or a mark; then it switches to the line tool. Can be also tapped and dragged; then it switches to the line tool and after realising switches back to the color picker. Can also be tapped on number bars.

**Ruler**: tap and hold on a box, square, cross, mark or clue to measure the lenght of the selected line. Tap and drag to measure the lenght of the selected line. This tool is very useful for measuring the distance of empty squares when doing the *overlapping technique* or when measuring the already colored squares - boxes. Detailed explanation:

- When tapping and holding on a box, square, cross or mark - measures the height and the width of the selected box, square, cross or mark (must be a continues line).
- When tapping and holding on a clue (in number bars) - measures the and calculates the lenght of that line
__with__crosses. - When tapping and dragging a box, square, cross or mark - measures the lenght of the selected line (it doesn't matter if it's a box, square, cross or mark).
- When tapping and dragging on a clue - measures and calculates the lenght of the selected clues
__with__crosses.

## Tips (colored and black-and-white)

- Look for full lines. You can enable "suggest to fill trivial lines at start" and this will do it for you. Enabling this is not recommended for progressing quicker through the Adventurers Guild, since it reduces rewards.
- Look for overlaps.
- Look for simple boxes and crosses.
- Start on the borders of the puzzle.