Plankway #19 · Tuesday, 13 October 2026

Plankway #19 was the puzzle for Tuesday, 13 October 2026. Its difficulty is easy: a 7 × 7 grid with 12 islands and 1 reef. The solver needs 21 logical steps; the hardest technique it needs is At least one.

Tuesday puzzles stay on a 7 × 7 grid, with a few more islands and a need for "at least one" reasoning. A reef played a part in 3 steps, hiding a neighbour that would otherwise be in line.

Techniques used

• Bridge limits: 8 steps
• Every bridge counts: 9 steps
• Crossing bridges: 2 steps
• Full island: 1 step
• At least one: 1 step

The key step

The hardest step in this puzzle is step 6. This is the board just before it; in blue what the step adds, in red what it rules out.

Step by step

Every step follows from what is already certain. Columns are lettered, rows numbered. Read along to where you got stuck, then try to continue on your own.

1. Bridge limits: The 1 in E7 does not have the room for more: at most one bridge between the 2 in E5 and the 1 in E7 and at most one bridge between the 2 in A7 and the 1 in E7.
2. Bridge limits: The 1 in D4 does not have the room for more: at most one bridge between the 1 in D4 and the 3 in G4 and at most one bridge between the 1 in D4 and the 1 in D6.
3. Bridge limits: The 1 in A2 does not have the room for more: at most one bridge between the 1 in A2 and the 3 in C2. A reef plays a part here.
4. Every bridge counts: The 1 in A2 needs every bridge it can still get: one bridge between the 1 in A2 and the 3 in C2. A reef plays a part here.
5. Bridge limits: The 1 in D6 does not have the room for more: at most one bridge between the 1 in D6 and the 2 in G6.
6. At least one: The 5 in C5 cannot get enough from its other neighbours: at least one bridge between the 3 in C2 and the 5 in C5, at least one bridge between the 5 in C5 and the 2 in E5 and at least one bridge between the 3 in A5 and the 5 in C5.
7. Crossing bridges: A certain bridge blocks the connections that would cross it: no bridge between the 1 in D4 and the 1 in D6.
8. Every bridge counts: The 1 in D4 needs every bridge it can still get: one bridge between the 1 in D4 and the 3 in G4.
9. Every bridge counts: The 1 in D6 needs every bridge it can still get: one bridge between the 1 in D6 and the 2 in G6.
10. Crossing bridges: A certain bridge blocks the connections that would cross it: no bridge between the 2 in E5 and the 1 in E7.
11. Every bridge counts: The 2 in E5 needs every bridge it can still get: a double bridge between the 5 in C5 and the 2 in E5.
12. Every bridge counts: The 1 in E7 needs every bridge it can still get: one bridge between the 2 in A7 and the 1 in E7.
13. Bridge limits: The 3 in C2 does not have the room for more: at most one bridge between the 3 in C2 and the 2 in G2.
14. Bridge limits: The 2 in A7 does not have the room for more: at most one bridge between the 3 in A5 and the 2 in A7.
15. Every bridge counts: The 3 in A5 needs every bridge it can still get: a double bridge between the 3 in A5 and the 5 in C5 and one bridge between the 3 in A5 and the 2 in A7. A reef plays a part here.
16. Full island: The 5 in C5 already has all its bridges: one bridge between the 3 in C2 and the 5 in C5.
17. Every bridge counts: The 3 in C2 needs every bridge it can still get: one bridge between the 3 in C2 and the 2 in G2.
18. Bridge limits: The 2 in G2 does not have the room for more: at most one bridge between the 2 in G2 and the 3 in G4.
19. Every bridge counts: The 2 in G2 needs every bridge it can still get: one bridge between the 2 in G2 and the 3 in G4.
20. Bridge limits: The 3 in G4 does not have the room for more: at most one bridge between the 3 in G4 and the 2 in G6.
21. Every bridge counts: The 3 in G4 needs every bridge it can still get: one bridge between the 3 in G4 and the 2 in G6.

The solution

Play today’s puzzle