The case notes
Reserve three digits across three cells
A naked triple works like a pair, with three cells reserving three digits. Here the first row has five gaps. Watch a worked example, then try the idea in a puzzle.
Put it into practice
Three cells · three digits
A naked triple works like a pair, with three cells reserving three digits. Here the first row has five gaps.
Row needs 1 through 5
The row needs one, two, three, four and five. Its first three cells sit in the same box.
First three cells: {1, 2, 3}
That box already has four and five. So the first three row cells can use only one, two and three. We do not yet know their order.
1, 2, 3 are reserved
Those three cells must take one, two and three in some order. The other two gaps in this row cannot use any of those digits.
r1c4 = 4
The fourth cell is now four or five. There is a five lower down in its column, so the fourth cell is four.
Read the transcript
A naked triple works like a pair, with three cells reserving three digits. Here the first row has five gaps. The row needs one, two, three, four and five. Its first three cells sit in the same box. That box already has four and five. So the first three row cells can use only one, two and three. We do not yet know their order. Those three cells must take one, two and three in some order. The other two gaps in this row cannot use any of those digits. The fourth cell is now four or five. There is a five lower down in its column, so the fourth cell is four.
