Puzzle types and constraints

There are many types of cryptic puzzles, including variations on common types. The below lists some of the more common types.

Magic Square
A magic square is a 3x3 grid where the rows, columns, and numbers add up to the same number, 15.

First appearance

Thermo
In thermometer shapes, numbers must increase as they move away from the bulb.

First appearance

Knight
A digit cannot lie a knight's move in chess away from another cell containing the same digit.

First appearance

Sandwich
Numbers outside the grid indicate the sum of the cells sandwiched between the 1 and 9 in that row or column.

First appearance