# Ninekeep: Sudoku — Hints that teach the technique > Educational Sudoku game with advanced technique hints and two play modes. (iPhone/iPad app by Velcairn Studios LLC.) - Source: https://appshunter.io/ios/app/ninekeep-sudoku/id6787771732 (this page in markdown: same URL + `.md`) - Developer: [Velcairn Studios LLC](https://appshunter.io/developer/6787771734) - Category: Games, Board, Puzzle - Price: Free - Rating: 5.00/5 from 1 App Store ratings - Age rating: 4+ - Requires: iOS 17.0 · 13 MB - Languages: American English - Released: 2026-07-16 - Data updated: 2026-09-10 - Monetization: free with in-app purchases - User reviews in markdown: https://appshunter.io/ios/app/ninekeep-sudoku/id6787771732/reviews.md ## What is Ninekeep? Sudoku that teaches you, with nothing in the way. A hint here names the technique it used, shows you where to look, and explains the reasoning before it will place anything. Tap once and the board is there, ready to solve. No spin-to-win wheel, no animated helper nudging you toward a hint you didn't ask for. TWO WAYS TO PLAY Classic is the nine-by-nine grid you know, at four difficulty levels from Easy to Expert. Sums (the variant usually called Killer Sudoku) starts with no given digits at all. The grid is drawn into cages instead, each printed with the total its squares add up to, and you work back from the arithmetic. Sums has its own four difficulties and keeps its own best times. HINTS THAT TEACH There are thirteen solving techniques in the ladder, from naked pairs up through X-Wing, Y-Wing, Swordfish and Colouring. A hint names the one that applies, points you at the cells, and explains why it works. It still won't tell you the digit until you ask it to place one. Solve using a technique without help and the app records that you can do it. What you have learned stays visible, and there is no score attached to it. BOARDS THAT DON'T RUN OUT Every puzzle is built on your device, so the supply never ends and the daily never comes around twice. Difficulty means something specific here: a Hard board genuinely needs the techniques the word implies, rather than just showing you fewer numbers. THE DAILY LEDGER One puzzle a day seals into your Ledger when you finish it, and the year fills in as you go. A day you missed entirely can still be sealed later. Your stats stay simple. Current streak, best time, boards sealed, the last thirty days at a glance, and a twelve-week chart of your solve times. There's no score for how often you show up. MARKS AND THE BINDERY Solved boards earn Marks, which unlock themes in the Bindery. Marks come from solving and from nothing else: they can't be bought, and they can't buy a hint or repair a streak. ON YOUR HOME SCREEN A Home and Lock Screen widget carries your streak and whether today's board is sealed yet. You can start today's board by asking Siri, or straight from Spotlight. Your Ledger syncs between your iPhone and iPad through your own iCloud account, so there's no Ninekeep account to set up and no server of ours in the way. WHAT THINGS COST Ninekeep is free to download. Two hints per board are free, along with notes, auto-check, retries, and undo. If you want another hint after that, you can watch a short video for one, or buy Remove Ads once and skip the watching for good. Nothing plays on its own, there are no banners or interstitials, and the only ad in the app is one you asked for. Pencil marks will fill themselves in if you'd rather not transcribe them, and they tidy up as you place digits. One undo takes the whole thing back. You can hide the timer, if the clock is the part that makes it feel like a test. Challenge mode gives you a mistake limit if you'd rather play under pressure. On iPad it's built for the screen rather than stretched across it, with a three-pane layout, a keypad down the side, and a result view that splits in two. The numbers are a dark ink serif on a warm cream board, with a little gold on the things worth noticing. Sound and haptics are yours to keep or turn off. ACCESSIBILITY VoiceOver labels the board, the keypad, and every control. Text scales from the smallest size up to the largest accessibility setting, and the layout still holds together. Reduce Motion and Reduce Transparency are both honored, and nothing depends on color alone. Made for a coffee break, a train ride, or a few quiet minutes before bed. On iPhone and iPad. ## Key features - Teaches Sudoku solving techniques - Classic and Sums (Killer Sudoku) modes - Customizable difficulty levels - Unlimited puzzle generation - Daily Ledger for tracking progress - Unlockable themes via in-game currency ## Frequently asked questions about Ninekeep ### Does Ninekeep have ads? Yes, Ninekeep contains advertisements. You can choose to watch a short video for an extra hint, or purchase 'Remove Ads' to permanently disable this option. ### How much does Ninekeep cost? Ninekeep is free to download. Basic features like hints, notes, and undo are included. Additional hints can be earned by watching ads or through a one-time purchase. ### What devices does Ninekeep support? Ninekeep is available on iPhone and iPad devices. ### What is the age rating for Ninekeep? Ninekeep has an age rating of 4+, making it suitable for a wide range of players. ### How often is Ninekeep updated? The latest version, 1.1.0, was released on August 19, 2026, indicating regular updates from the developer. ### Can I play Ninekeep offline? Yes, puzzles are generated on your device, allowing for offline play. The game does not require an internet connection to generate new boards. ### What makes Ninekeep's hints unique? Hints in Ninekeep name the technique used, show where to look, and explain the reasoning before placing any numbers. This educational approach helps players learn and improve their skills. ### How does the 'Daily Ledger' work in Ninekeep? The Daily Ledger seals one puzzle per day into your record as you complete it. It tracks your current streak, best times, and provides a visual overview of your recent performance. ## Version history (last 2 releases) ### 1.1.0 — 2026-08-19 Ninekeep builds its puzzles on your device now, so boards stop running out and the daily never comes around a second time. Difficulty means something specific too: Hard and Expert boards now genuinely need the techniques those words imply, rather than just showing fewer numbers. There's a second way to play. Sums boards start with no given digits at all. The grid is drawn into cages instead, each printed with the total its squares add up to, and you work back from the arithmetic. It's the variant usually called Killer Sudoku. Four difficulty levels like the classic boards, and its own set of best times. Hints teach now. Instead of just filling in a square, a hint names the technique it used, shows you where to look, and explains the reasoning. It still won't tell you the digit until you ask it to place one. There are thirteen techniques it can teach, up through X-Wing, Y-Wing, Swordfish and Colouring, and the app keeps a record of the ones you have solved with unaided. The first two hints on any board are free, the way they always were. If you want another after that, you can watch a short video for it, or turn ads off for good with a one-time purchase in Settings. Saying no to the video leaves the board exactly as it was, and there are no ads anywhere else in the app. Your Ledger now syncs between iPhone and iPad through your own iCloud account. There's no account to make and no server of ours involved, and if you aren't signed in to iCloud everything stays on the device and works the same. There's a widget too, for the Home and Lock Screen. It carries your streak and whether today's board is sealed yet. Pencil marks can fill themselves in, if you would rather not transcribe them by hand. They are only ever the candidates you could have worked out yourself, and they tidy up as you place digits. One undo takes the whole thing back. Solved boards now earn Marks, which unlock things in the Bindery. Marks are earned by solving and by nothing else. They cannot be bought, and they cannot buy hints, streak repairs, or anything that touches the board you are on. The four themes you already have stay free. If you broke a streak by missing a single day, the home screen offers it back for one video. It covers one missed day only, and only the day after. The ledger fills in backwards now too, so a day you missed entirely can still be sealed later. You can hide the timer, if the clock was the part that made it feel like a test. And you can start a board by asking Siri, or straight from Spotlight. — John ### 1.0 — 2026-07-16 No release notes. ## Apps similar to Ninekeep | App | Rating | Price | Category | | --- | --- | --- | --- | | [Sudoku 9x9 Game](https://appshunter.io/ios/app/sudoku-9x9-game/id548569056) | 3.9 (22) | Free | Games | | [Lemmings: Strategy & Puzzle](https://appshunter.io/ios/app/lemmings-strategy-and-puzzle/id1238114713) | 4.7 (25,521) | Free | Games | | [Sudoku - Puzzle Challenge](https://appshunter.io/ios/app/sudoku-puzzle-challenge/id6758075653) | — | Free | Games | | [Sudoku Daily: Brain Puzzles](https://appshunter.io/ios/app/sudoku-daily-brain-puzzles/id6742624265) | — | Free | Games | | [Sudoku Joy: Number Master Game](https://appshunter.io/ios/app/sudoku-joy-number-master-game/id1460985516) | 4.9 (748) | Free | Games | ## More apps by Velcairn Studios LLC - [Tide & Stone: Block Puzzle](https://appshunter.io/ios/app/tide-and-stone-block-puzzle/id6792006273) - [Glyphrail: Daily Word Chain](https://appshunter.io/ios/app/glyphrail-daily-word-chain/id6792006633) All apps by Velcairn Studios LLC: https://appshunter.io/developer/6787771734 --- *Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-09-10.*