Free for teaching
The player manual, teaching activities and answers to your questions, all in one place.
Two books — to read as PDF in the browser, or to take along as EPUB — plus the guide built into the app, 📖 Game guide, in all twenty-six languages, readable offline like everything else. The screenshots are not mock-ups, and every grid shown carries its code: reopen it in the game and play what you are reading.
Everything the game can do, mode by mode, setting by setting: the three base modes, the sixteen themed sets, the five boards, the generation options, the helpers, the keyboard, the game code letter by letter, and the two versions.
Written for you, the teacher, and not for the child — it is not a manual for learning to play, the other book takes care of that. This one answers a different question: what do you do with the game, with twenty-five pupils and fifty minutes? A lesson in four stages — on the board, in groups, alone, as homework — and sheets sorted by notion, from first additions to fractions and decimals. None of it is an instruction: you are in charge of your classroom.
No, because the game starts at two cells a side, where there is nothing to look for, and grows one cell at a time. The rule stays the same from 2×2 to 26×26; only the length of the reasoning increases, very gradually. You choose the starting size, you choose the final one, and nothing forces you further than the class can follow.
Puzzles within the free range can be completed in full. Beyond that range, you can try advanced options with a filling limit. Full details are on the Versions page.
€2 a year, or €10 for life, your choice, on Google Play. The game refuses the two usual ways of funding a free app — advertising and data collection — and asks for no account: it is free for teaching and paid for by those who take to it. The free version lets you try everything, with no time limit; the full one lifts the filling limits and adds the solving list and the player's path to printing. The licence you buy also moves to the web version, through a QR code from the phone. The store handles the payment, never the game: it sees no payment data.
On the device, and nowhere else: nothing is sent, nothing is saved online, nothing follows an account. The flip side: if you uninstall the game, your games disappear with it, and there is nowhere to restore from. If a game matters to you, copy its state code — the string carrying the grid and everything you wrote in it — and keep it wherever you like.
Yes. The code does not carry the grid but what is needed to rebuild it, and it starts with the version of the generator that made it — G1, G2… Since earlier generators are kept, a code never stops working: the one you hand out this year will open the same grid in five years. A check key at the end catches any typo and any swap of two neighbouring characters.
Through the game code — a pill under the tools, one tap copies it — which the other person types, pastes or scans as a QR from the Code button on the home screen. To pass on a game in progress, with your values and pencil marks, the button marked with a grid copies the state code. And when there is neither screen nor phone, paper: the printed grid carries its code and its QR.
Yes: a dialog in the app lets you type a grid's symbols — letters in lower or upper case, syllables, words, specific digits, even emojis. The rule does not change, and the game code carries the symbols: the grid is shared by code or QR like any other. That is how a sudoku becomes a reading exercise — three examples in the Learn section.
Entirely. The app declares no network permission: once installed, it never needs the internet again, and a school has nothing to open in its firewall. The web version only needs the network to load the page the first time — and, if you have transferred your licence to it, to check it.
Play InZeDoku on an Android phone or tablet, on a Windows computer and in your browser. The web version opens without installation at web.inzedoku.com.
A keyboard and mouse plugged into a phone or tablet work too: nothing is reserved for the desktop.
Yes, both ways, and without an account: the web version at web.inzedoku.com has every geometry, every mode and every level. Each side can show a QR and scan one — Code → Scan a QR — and each side can copy a code and paste one — Code → Paste a game. The QR button shows the grid, or the game as it stands, values and pencil marks included, if you flip the switch; the grid button copies the game's state code: eleven characters without pencil marks, one more per value placed.
The same code gives exactly the same grid on both sides — measured grid by grid, not assumed. So you pick up right where you were, and you can go back the other way as often as you like.
Without a licence, it has the same range as the free version: everything opens, and beyond that it is a demonstration. With the full version on your phone, show it the licence QR: the web version becomes full. Only one browser can hold it at a time, and it checks it online every five minutes; if the check fails — offline, or licence passed to another browser — it goes back to free without closing or losing anything. The phone, for its part, always keeps its licence, and can reset it to take it back from a browser that would still hold it.
Two-finger zoom and panning work everywhere, but a 16×16 does not fit comfortably on a phone. The first time you go past nine a side, the game tells you itself: those sizes play better in the browser, on a large screen, with a mouse and keyboard. Hand it the game, as explained above, and carry on on the other side.
It can flag conflicts — placing a value that contradicts an already-filled cell — but that setting is off by default. On the other hand, it never tells you a value is wrong with respect to the solution as long as it contradicts nothing: that would be playing in your place. The preview shows everything — but that is a gesture you ask for explicitly.
Yes. The Colour blindness setting is chosen by type — deuteranopia, protanopia, tritanopia, achromatopsia — because the different forms are not compensated the same way. In Colodoku, a symbol is added over the colour; in multidoku, the frames switch to an axis your type distinguishes, or to stroke patterns when no colour is perceived. And some of the game's marks rely on colour in no setting at all: the full badge of a correct cage, the red cross of a duplicated colour, the black dot of a given value.
Twenty-six: the twenty-four official languages of the European Union, plus Turkish and Luxembourgish — and decimal notation follows the language, point or comma. The language is changed from the ☰ menu on the home screen, not buried in the settings: it is the first setting anyone needs.
To discover the game, prepare to use it in class or discuss a project, talk with Jacques Lovi.
When booking, mention InZeDoku and the purpose of your meeting.
