Learning a strategy

How I pick up one technique I do not know yet: read it, think it through, find it on a real puzzle, walk through why it works, and then try to spot it myself.

Free and Premium. Reading the explanation of any technique is free. Practising a technique on puzzles built for it, and the Step by step mode, need Premium.

Note

Not a checklist to clear

Most of what you will ever use, such as Hidden Pair, Naked Triple or Pointing Pair, you will start to notice on your own just by solving puzzles with the Solving routine. This guide is for the techniques that do not click that way: a way to sit down deliberately with one unfamiliar pattern and learn it.

There is no progress bar, nothing to unlock and no level to reach. Pick a technique because you are curious about it, go at your own pace and stop the moment it clicks, or whenever you have had enough for today.

Step 1 Premium

Pick one you do not know

I open the gear menu and choose Practice technique…. It lists every technique Grid9 knows, grouped by how advanced it is. I pick one I do not reliably spot myself yet.

Swordfish is a good example for this guide: three rows, three columns, one digit. It is genuinely hard to see until you have looked at a few.

Close-up of the Practice technique list — Techniques are grouped by difficulty. Tap one to practise it.

The Practice technique menu listing techniques grouped as Easy, Medium and Hard — The technique list, grouped by difficulty. Click to enlarge.

Step 2

Read it before you hunt

Before I go looking for the pattern on a real board, I open Explanation, the small “i” next to the hint. It is worth reading properly: what the pattern looks like, why it works and what it lets you eliminate. Each explanation starts with a short core rule and has a diagram.

Hunting for something you do not understand yet is just guessing with extra steps.

Close-up of the core rule of an Explanation page — The core rule comes first, in a sentence or two.

Close-up of the diagram on an Explanation page — Then a small diagram that shows the pattern.

Reading the explanation of any technique is free.

An Explanation page with a core rule, a diagram and the reasoning — Explanation: the core rule, a diagram and the why. Click to enlarge.

Step 3

Sit with it first

Then I stop and actually think it through, sometimes with paper and a pencil, tracing the logic by hand: which candidates, which rows and columns, and why they lock together the way they do.

I do not rush to a puzzle. Skipping ahead to “just show me an example” skips the part that makes a pattern stick.

Step 4 Premium

Try it for real

Only then do I bring it to a real puzzle. Grid9 gives me one where the technique is needed, with a badge showing which technique I am practising. I open the hint ladder and walk it down one rung at a time. Fish techniques such as Swordfish get an extra rung, Which lines?, before the hint narrows down to exact cells.

Where?Which lines?Which cells?Why?Apply

At each rung I try to actually look for the pattern myself before I tap through to the next one.

Close-up of the Which lines step for X-Wing — Each rung narrows it down. Here: which two lines form the X-Wing.

The hint ladder for X-Wing with Where, Which lines, Which cells and Why — X-Wing in practice mode, with the highlighted pattern and its reasoning. Click to enlarge.

Step 5 Premium

Walk it through again

Once I have reached Why?, or even after I have applied the move, I tap Step by step. It is more pedagogical than the ladder: it walks the whole reasoning chain one link at a time, forwards and backwards. That is worth doing even when I already know the answer.

Lost the thread? Step back and watch the link again. Seeing why it is true is different from seeing that it is true.

Close-up of the Explanation and Step by step buttons — The two buttons above the ladder in practice mode.

Close-up of the Step by step panel — One link of the chain at a time.

The Step by step panel explaining an X-Wing one link at a time — Step by step shows one link of the chain at a time. Click to enlarge.

Step 6 Premium

Do it again, a few times

Then I do it again: Practice technique… once more, same technique, a few more puzzles, until the shape stops feeling like a lucky find and starts to look familiar.

Some techniques take two puzzles to click and others take five. There is no fixed number, and no way to get it wrong by taking longer.

Step 7 Premium

Mark it yourself, then check

Eventually I flip it around. Before opening any hint, I tap the cells I think form the pattern. Practice mode remembers every tap as a soft highlight, with no commitment and easy to undo. Then I walk the hint ladder and see whether I was right.

Some puzzles hide more than one occurrence of the same technique. Two separate Swordfish in one grid is not unusual. I mark what I found, check it, and then go looking for a second one before I move on.

Close-up of a practice grid with the cells I guessed marked in teal — The teal cells are my guess. The ladder tells me if I was right.

A practice puzzle where the cells I think form the pattern are marked in teal — My guess is marked on the grid, the ladder then shows if it was right. Click to enlarge.

Step 8

One day you will just see it

There is no test at the end and nothing that marks a technique as done. You will know it worked the same way everything else in Grid9 works: mid-game, on some ordinary puzzle, you will just see it.

That is the point. Not finishing a guide, but folding one more pattern into how you already play, back in the regular Solving routine.

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Try it yourself

This guide is also built into the app, under the gear menu. Reading is always free.

Coming soon to the App Store