Runelocked Chest

To unlock these wq you have to find
[item=169216]
which can be found in all the arcane chest in Nazjatar

There are 18 Runelocked Chest World Quests.

Easy Runelocked Chest: Yellow
Easy Runelocked Chest: Red
Easy Runelocked Chest: Purple
Easy Runelocked Chest: Orange
Easy Runelocked Chest: Green
Easy Runelocked Chest: Blue

Medium Runelocked Chest: Yellow
Medium Runelocked Chest: Red
Medium Runelocked Chest: Purple
Medium Runelocked Chest: Orange
Medium Runelocked Chest: Green
Medium Runelocked Chest: Blue

Hard Runelocked Chest: Yellow
Hard Runelocked Chest: Red
Hard Runelocked Chest: Purple
Hard Runelocked Chest: Orange
Hard Runelocked Chest: Green
Hard Runelocked Chest: Blue

These are part of the achievement "Puzzle Performer"

To unlock these World Quests you have to first find a Silver Knife
which can be found in any of the arcane chests in Nazjatar

This puzzle game is optional, so if you don't like it, don't play it.
I personally like these quests. It gives me a break from killing.

The mechanics work like this:

The game consists of a 8 x 8 grid which is composed of 6 different colored runes.

1] Click on any rune.

2] Click on any adjacent rune and those two runes will swap positions.

3] If, by swapping those two runes, you cause 3 runes in a row to all be of the same color, then those three runes will be destroyed.

4] If, by swapping those two runes, you do not cause 3 runes in a row to all be of the same color, then those two runes will swap back to the positions they were in and nothing happens.

5] An adjacent rune is considered to be to the left, right, up, or down.

6] A row can be left to right or up and down.

7] When runes are destroyed, each rune (and all the runes in that column above that rune) will fall downward.

8] If you cause more than 3 runes to be in the same row or column, then all of the runes of that color will be destroyed. So, for example, if you cause 4 runes to be the same color, all 4 of those runes will be destroyed.

9] If you get stuck, you can exit the game and restart it.
I personally have never gotten stuck, but one time for me the quest completed before I reached the goal. Apparently, that time, randomness left the puzzle unsolvable.

10] To exit the game, click on the Arcane buff in the upper right of your screen.

The object of the game is to destroy a fixed number of runes of one particular color, but you can destroy as many runes of any color to keep changing the pattern of the grid.

OK, if you've never played candy crunch or any knockoffs of this, like me you'll be rather puzzled and frustrated about the lack of information on how to solve these. Here's the routine:

1) you move a piece by clicking on the piece you want to move, then clicking on the piece that is occupying the space where you want to move the first piece you clicked on.

2) You can only move one space, either up, down, left or right. You cannot move diagonally.

3) You can move a piece ONLY if you move it to a slot that creates a line of 3 or more of the same design/color, without spaces. That's it! No other move allowed.

4) When you create a line, either horizontal or vertical, not diagonal, those pieces in that line disappear and pieces move from above to fill the vacated spaces. If the pieces that disappear are the color you are trying to destroy, then they add to your total of destroyed pieces. If they are not the required color, then hopefully the movement of pieces offers other chances to destroy the right color.

5) I've found that it's not worth doing too much strategizing; there usually just isn't opportunity for it. Do keep an eye out for possible lines of the required color, but If you just make lines of 3 or more of any color to move the pieces around enough, eventually you will destroy enough of the right color to complete the puzzle.