Fill each cell with a digit from 1-9. Cells sharing an edge can't have the same digit. Each horizontal row and vertical column contains a non-repeating consecutive set of digits (like 23456) in any order. The blue circles and red squares combined form a complete set of the digits 1-9. A digit in a blue circle indicates how many of that digit appear in the entire puzzle. A digit in a red square indicates that the digit does not appear exactly that many times in the puzzle. EG if there were four 4s and six 5s in the grid, the 4 would go into a circle and the 5 in a square.