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Sravan Nerella

Support

Sudoku Collector v1.0 and later.

Contact

Email: sudoku-support@sravannerella.com

We aim to reply within 5 business days. Thanks for your patience.

If you're reporting a bug, please include:

FAQ

How do I import a puzzle from a magazine, website, or screenshot?

Open the Dossier tab → + in the top-right → Add Puzzle. You can either tap each given digit onto the empty grid, or paste an 81-character puzzle string. Sudoku Collector recognizes the standard 81-character format and three other common formats — including the ones used by most Sudoku websites. The app checks that the puzzle has exactly one solution, works out which techniques it teaches, and saves it to your Dossier. From there it plays just like a built-in puzzle, with the full Train hint sequence available.

The hint says one thing, but I'm seeing something different — why?

The Train hint looks at the puzzle as it is right now, on every tap — not the original starting position. So if you've already solved part of the puzzle in a different order than the app's preferred path, the hint adjusts to where you actually are. That's intentional: two players who take different routes through the same puzzle should both still get a correct next step. If you think a hint is genuinely wrong — for example, it suggests a digit that's already been eliminated — please email us with the puzzle and a screenshot.

Do my puzzles sync between iPhone and iPad?

Not yet. In v1.0 your progress, Dossier, and settings live on each device on their own. Cross-device sync is on the roadmap, but we won't ship it until we can do it without making you sign in to an account and without sending your puzzles to a server. For now, please treat each device as its own player.

How do I keep my progress when I get a new phone?

Your Dossier, daily progress, and pack history are stored in the app's regular on-device storage — which the standard backup and transfer tools built into iOS and Android pick up automatically. You don't need to do anything special inside Sudoku Collector.

iPhone → new iPhone. Use Quick Start when setting up the new phone (hold the old phone near the new one), or restore from an iCloud Backup. Either brings the app and all of its data across. Make sure iCloud Backup is on now: Settings → [your name] → iCloud → iCloud Backup → On.

Android → new Android. Use the "Switch phones" / "Copy apps & data" flow during setup, or restore from your Google Backup. Confirm backup is on: Settings → System → Backup → On.

iPhone ↔ Android. Switching ecosystems isn't supported. iCloud and Google Backup don't share a format, and Sudoku Collector itself doesn't sync across the cloud (no accounts means no cloud copy). If you're switching between iOS and Android, you'll start fresh on the new device.

How do I reset my progress?

The cleanest way is to delete the app and reinstall it. iOS and Android remove all of the app's local data along with the app, so a fresh install starts you back at zero. We deliberately didn't add a "Reset Progress" button — we'd rather not put something in the menu where one careless tap could wipe years of solves.

The app says "offline" but I have Wi-Fi — what's going on?

Sudoku Collector is built to work offline. Every pack and every puzzle ships inside the app, so you can play through the whole library without ever connecting to the internet. The app does reach out to the network in two places: at launch, to check for new puzzle packs, and once a month, to download the next month's daily puzzles in one bundle. Both are optional and can be turned off in Settings → Pack updates. If you do turn them off, the daily quietly falls back to puzzles generated from your installed packs — you still get twelve a day, every day.

So if you see an "offline" indicator while your Wi-Fi is working, it just means the app couldn't reach the server on this particular launch. Everything you already have on the phone keeps playing normally.

How do I change difficulty?

Difficulty is personal — what's hard for one solver is muscle memory for another. Rather than guess what "Medium" means for you, we sorted every technique in the game into 8 tiers (Tier 1 is the gentlest, Tier 8 is the hardest), so you get to set your own range.

Two places to do that:

You have full control. The app nudges your range upward as you grow, but you can always pull it back.

Why does the same puzzle look different when I replay it?

Every puzzle in Sudoku Collector has a shape underneath it — the relationships between cells that make a Naked Triple a Naked Triple, or a Skyscraper a Skyscraper. The numbers you see on the surface, and which row, column, and 3×3 box they sit in, are just one way of dressing up that shape. Each time you finish a puzzle and come back to it, we redress it. Same lesson, fresh-looking board.

This is intentional. The point of replaying is to get faster at spotting the pattern, not to remember where the digits went last time. Replaying the same shape in different visual arrangements trains your eye for the pattern itself — which is what you actually need when you meet a similar puzzle in a magazine or on the web. The technique you're learning, the difficulty, and the number of moves are all unchanged from one replay to the next. Only the dressing changes.

I think the app classified a puzzle wrong — how do I report it?

A quick note on the labels first. Every puzzle is named for the hardest technique it requires — the move you can't avoid somewhere in the solve, no matter which path you take. That label stays the same across replays, even though the board redresses itself each time (see the question above). The order you encounter techniques in can shift between plays — you might hit a Hidden Pair before an X-Wing one day and after it the next — but the X-Wing is still required, and that's what the puzzle is named for.

A real misclassification is when the labeled technique is never needed to finish the puzzle. If you solve a puzzle labeled "X-Wing" and no X-Wing ever shows up on the way, please email us the puzzle (the 81-character string), what the app labeled it as, and what you think the actual hardest move was. We read every report.

"I solved with a Naked Triple at step 5 instead of the X-Wing the hint showed me" usually isn't a misclassification — it's just two valid paths through the same puzzle, both correct. The label is about the required hardest move across the whole solve, not whichever technique a solver happens to reach for first at a given step.

Will you add Killer Sudoku / Samurai Sudoku / other variants?

Not in v1.0. The whole app is tuned to classical 9×9 Sudoku — every technique, every hint, every daily puzzle is calibrated to those rules. Adding a variant would mean redoing a lot of that work and would split our focus from doing one thing well. We may revisit after v1 settles in; no commitment yet.

Common issues

"Puzzle not accepted" when importing

This happens for one of two reasons, and the error message will tell you which:

  1. Multiple solutions — the puzzle as given could be finished more than one way. Sudoku Collector only accepts puzzles with a single unique answer. Add more starting digits.
  2. No solution — the starting digits contradict each other somewhere. Double-check your input for typos against the original puzzle.

Train hint cleared a mark I wanted to keep

Train hints write to the same notes on your board as you do — they don't have a separate protected layer. Tap Undo (the curved-arrow icon at the top-left of the board) to bring back anything a hint scrubbed. Undo covers every action on the board, hints included.