Solving First Landfall, step by step
A complete walkthrough of Printable No. 01: every coastline, bridge and number, with the reason each one must be true.
This is the full solution path for First Landfall, Level 1 in the app and Printable No. 01. Print it and follow along, or try it yourself first and come back when you're stuck.
Squares are named the way the printable labels them: columns A–F from left to right, rows 1–6 from top to bottom. So A1 is the top-left corner. “Bridge B1–C1” means those two squares are on the same island. “Coastline B2–B3” means a coastline runs between them.
The shape of the solve
Steps 1–7: the top-left corner. C1, the square with the given 2, is boxed in on two sides, so its island must grow left. Each step leaves only one way out, and the island snakes from C1 through B1, A1, A2 and A3 to B3. That's six squares, so coastlines close around it. The coastlines then seal off the six squares in the bottom-left corner, which form the second island.
Steps 8–10: counting. A few only-way-out moves follow. Then comes the first counting move: a coastline between D6 and E6 would trap 8 squares, which can't be split into islands of six.
Steps 11–27: numbers. With two islands mapped, the numbers flow. Most are “last number standing” moves, with a couple of hidden singles.
Steps 28–41: numbers draw the rest of the map. Two 5s face each other across D5–D6, and two 1s across D2–E2 and E1–E2. That gives coastlines, which seal the last islands.
Steps 42–44: finishing. Three final numbers complete the board.
Every step
These steps and explanations come straight from the app's hint engine, the same reasoning you see when you tap Show me how.
| # | Move | Why it must be true |
|---|---|---|
| 1 | Bridge B1–C1 | This cell must grow into an island of six, and this is the only edge left open. |
| 2 | Bridge A1–B1 | These 2 cells must grow into an island of six, and this is the only edge left open. |
| 3 | Bridge A1–A2 | These 3 cells must grow into an island of six, and this is the only edge left open. |
| 4 | Bridge A2–A3 | These 4 cells must grow into an island of six, and this is the only edge left open. |
| 5 | Bridge A3–B3 | These 5 cells must grow into an island of six, and this is the only edge left open. |
| 6 | Coastline B2–B3 Coastline B3–C3 Coastline B3–B4 | These six cells are already bridged into a full island, so a coastline runs along its edge. |
| 7 | Bridge A4–B4 Bridge A5–B5 Bridge A6–B6 Bridge A4–A5 Bridge A5–A6 Bridge B5–B6 | Coastlines enclose exactly six cells here, so they must all be one island. |
| 8 | Bridge C2–D2 | These 2 cells must grow into an island of six, and this is the only edge left open. |
| 9 | Bridge C6–D6 | This cell must grow into an island of six, and this is the only edge left open. |
| 10 | Bridge D6–E6 | A coastline here would wall off 8 cells, which can't be split into islands of six. |
| 11 | 5 in A4 | Its row, column and island already use every other digit, so only 5 fits. |
| 12 | 1 in C4 | Its row, column and island already use every other digit, so only 1 fits. |
| 13 | 3 in A6 | In this island, this is the only cell that can take a 3. |
| 14 | 5 in C6 | Its row, column and island already use every other digit, so only 5 fits. |
| 15 | 2 in E6 | Its row, column and island already use every other digit, so only 2 fits. |
| 16 | 2 in B2 | In row 2, this is the only cell that can take a 2. |
| 17 | 6 in B5 | Its row, column and island already use every other digit, so only 6 fits. |
| 18 | 2 in A5 | Its row, column and island already use every other digit, so only 2 fits. |
| 19 | 4 in C5 | Its row, column and island already use every other digit, so only 4 fits. |
| 20 | 1 in F5 | Its row, column and island already use every other digit, so only 1 fits. |
| 21 | 6 in F1 | Its row, column and island already use every other digit, so only 6 fits. |
| 22 | 4 in A1 | Its row, column and island already use every other digit, so only 4 fits. |
| 23 | 6 in A2 | Its row, column and island already use every other digit, so only 6 fits. |
| 24 | 3 in C2 | Its row, column and island already use every other digit, so only 3 fits. |
| 25 | 6 in C3 | Its row, column and island already use every other digit, so only 6 fits. |
| 26 | 2 in F3 | Its row, column and island already use every other digit, so only 2 fits. |
| 27 | 5 in D5 | Its row, column and island already use every other digit, so only 5 fits. |
| 28 | Coastline D5–D6 | Both sides already contain a 5, so they can't be the same island. |
| 29 | Bridge C3–D3 Bridge C4–D4 Bridge C5–D5 Bridge C3–C4 Bridge D3–D4 Bridge C4–C5 Bridge D4–D5 | Coastlines enclose exactly six cells here, so they must all be one island. |
| 30 | Bridge E5–F5 Bridge E6–F6 Bridge E5–E6 | Coastlines enclose exactly six cells here, so they must all be one island. |
| 31 | 1 in D1 | Its row, column and island already use every other digit, so only 1 fits. |
| 32 | 5 in E1 | Its row, column and island already use every other digit, so only 5 fits. |
| 33 | 3 in B1 | Its row, column and island already use every other digit, so only 3 fits. |
| 34 | 4 in D2 | Its row, column and island already use every other digit, so only 4 fits. |
| 35 | 1 in E2 | Its row, column and island already use every other digit, so only 1 fits. |
| 36 | Coastline D2–E2 | Both sides already contain a 1, so they can't be the same island. |
| 37 | Bridge D1–E1 | These 4 cells must grow into an island of six, and this is the only edge left open. |
| 38 | Coastline E1–E2 | Both sides already contain a 1, so they can't be the same island. |
| 39 | Bridge E1–F1 | These 5 cells must grow into an island of six, and this is the only edge left open. |
| 40 | Coastline F1–F2 | These six cells are already bridged into a full island, so a coastline runs along its edge. |
| 41 | Bridge E2–F2 Bridge E4–F4 Bridge E2–E3 Bridge F2–F3 Bridge E3–E4 Bridge F3–F4 | Coastlines enclose exactly six cells here, so they must all be one island. |
| 42 | 5 in B3 | Its row, column and island already use every other digit, so only 5 fits. |
| 43 | 3 in D3 | Its row, column and island already use every other digit, so only 3 fits. |
| 44 | 4 in E3 | Its row, column and island already use every other digit, so only 4 fits. |
Notice that no step needs a guess. That's true of every one of the 1,001 levels: each was checked to be solvable from start to finish with explainable logic like this.
