Dots and Boxes puzzles

Dots and Boxes puzzles are endgame positions on 3×3, 4×4 and 5×5 boards. The task is to take at least a given number of the remaining boxes against the best defence. In every one, exactly one line is best, and the obvious move of taking boxes or giving the fewest away falls short.

Pick a number. A tick means you solved it in this browser.

A full game of Dots and Boxes
Easy
Medium
Hard

Easy

#1–14 · Before taking anything, ask who will have to open the next chain. Two boxes given away now can buy every box later.

#1Take 3 of 5
#2Take 7 of 9
#3Take 5 of 9
#4Take 3 of 5
#5Take 4 of 6
#6Take 5 of 9
#7Take 6 of 8
#8Take 7 of 9
#9Take 3 of 5
#10Take 4 of 6
#11Take 6 of 8
#12Take 7 of 9
#13Take 6 of 8
#14Take 4 of 6

Medium

#15–27 · Count the chains of three or more and the loops. If the count is wrong for you, look for a line that changes it, even at the cost of a box.

#15Take 11 of 16
#16Take 10 of 16
#17Take 10 of 15
#18Take 12 of 16
#19Take 6 of 10
#20Take 10 of 16
#21Take 13 of 16
#22Take 10 of 16
#23Take 10 of 16
#24Take 9 of 14
#25Take 9 of 15
#26Take 13 of 15
#27Take 4 of 6

Hard

#28–40 · On 5×5 the chains are long and the loops expensive. Work out the value of opening each component, and open the cheapest one for the opponent to take.

#28Take 13 of 23
#29Take 14 of 22
#30Take 14 of 25
#31Take 15 of 18
#32Take 11 of 17
#33Take 18 of 24
#34Take 15 of 25
#35Take 15 of 25
#36Take 19 of 25
#37Take 17 of 23
#38Take 17 of 25
#39Take 8 of 14
#40Take 14 of 23