Sudoku Made and maintained by Brian Hamilton and Karan Hamilton.
Brian builds the playable puzzle tools, while Karan helps test clarity, difficulty feel, and the player experience.
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Valentine’s Day sudoku with pictures instead of numbers
Valentine's Sudoku is classic sudoku played with nine Valentine’s pictures: the heart, rose, love letter, cupid heart, gift, chocolate, ring, teddy and bouquet. Each picture stands for a number and sits once in every row, column and box. Love here is a constraint: no picture repeats, and even the heart waits its turn.
The three views, the board sizes, how many pictures each level deals you and how the boards are made are common to every one of our 21 picture games; Themed Sudoku has all that. Here it is just the Valentine’s set, and the one trap in it.
The romance escalates with the board. Every themed game deals its pictures in order, the first four on 4×4, the first six on 6×6 and all nine on 9×9, and this set happens to read like a courtship. The 4×4 is the opening moves: heart, rose, love letter, cupid heart. The gift and the chocolate, the effort phase, arrive on 6×6. The ring, the teddy and the bouquet wait for the full 9×9, so the ring is kept for the most committed board.
If the 🎁 Gift looks familiar, it is the same picture as the Gift in Christmas Sudoku, and the 🍫 Chocolate is the last of the nine in Easter Sudoku. The other seven belong to this game alone.
Heart or cupid heart: how do you tell the two hearts apart?
This is the two-hearts problem, and the 4×4 has it from the start: the Heart is picture 1 and the Cupid Heart picture 4, so both are on the beginner board. In our phone-width screenshots from Chrome on Windows, at every size and in both themes, the two are the same glossy pink-red heart; the Cupid Heart is tilted, with an arrow through it.
The arrow never vanished in our screenshots, not even on 9×9, so the pictures are not identical. The trouble is the glance. Scan a row for “a heart” and both answer. The third picture, the Love Letter, is an envelope with a red heart on its front, so on the 4×4 three of the four pictures carry a heart. Your phone has its own emoji, and its arrow may be bolder or fainter than ours; the key above the board shows your device’s versions.
The game never mixes them up, because it compares numbers, not pictures. Switch to Both and each picture wears its number; the key above the board pairs each picture with its number too, on a phone as well. Tap a square holding a Heart and every other Heart lights up, but no Cupid Heart does. Numbers view removes the problem entirely: it is a 1 and a 4.
How do you solve a 4×4 Valentine’s sudoku?
Here is the problem on a real board, a 4×4 Easy deal from this game, hearts and all. The question is not which picture a square is missing but where one picture can go: pick the Heart, pick a box with no Heart in it, and let the Hearts already placed strike out squares along their rows and columns.
That is a hidden single. R3C3 is not settled by its own neighbours: its row, column and box leave it the Heart or the Love Letter. It is settled because no other square in the box can take the Heart. The Cupid Heart sits right beside it at R3C2, which makes this board a fair test: read that one picture wrong and the box seems to have no room for a Heart at all. Checked by an independent solver, the board has a single answer, and singles carry it all the way. A Heart put in the wrong square turns grey and adds one to the Mistakes count.
Is Valentine’s sudoku for couples or for kids?
Both, though it is a one-player puzzle: there is no two-player mode on this board. It shares well anyway.
Solve one 6×6 together, alternating moves, with one rule: every placement needs a reason out loud. Cheaper than dinner, and you learn how the other person argues.
For a real head-to-head, Multiplayer Sudoku takes turns on one shared grid, in plain numbers rather than hearts.
It is not only for couples. February also puts this board in classrooms and at kitchen tables: it is a calm activity for the over-sugared afternoon after the valentines are swapped, and the pictures are ones young children can name on sight. The heart-heavy theme bothers children not at all, and the logic is exactly as sharp as on any other board.
For a young child, start on the 4×4 in Pictures view, and if the two hearts begin to blur, switch to Both rather than to a bigger board: the trap is on the small board, and the numbers are what get a child past it. Sudoku for Kids has more on teaching the rules at home and in class, and children who get on better with digits than with hearts have 4x4 Sudoku.