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Rill strategy guide: how to solve every field

Rill is a daily path puzzle: draw one channel of water through every plot of a field, passing the numbered wells in order. The rules take ten seconds to learn. This guide is about the part that takes longer — seeing the answer instead of guessing at it.

Updated 19 October 2026 · Rill 1.0.3. Field sizes and modes on this page are read from the game's own puzzle generator. For the rules with pictures, see the official How to play Rill page.

The rules in one paragraph

Start at well 1 and draw the channel one plot at a time — up, down, left or right, never diagonally. The channel must water every plot exactly once, cannot cross itself, cannot pass through a fence, and must pass the wells in order (1, 2, 3 …), ending on the last well. Drag back along the channel to erase. That is all; everything below follows from those rules.

A worked example

Here is a five-by-five field with four wells and four fences (the gold bars). Wells 2 and 3 sit side by side, but a fence runs between them.

First pass — count the open sides of every plot. Every plot except well 1 and the last well is entered once and left once, so it needs exactly two links. A plot with only two open sides has no choice. That covers the four corners, and here the fences have cut seven more plots down to two open sides, including wells 2 and 3 themselves. Drawing every one of those links gives 18 of the channel's 24 links before any real thinking.

Second pass — let the order decide. What is left are five short pieces of channel and two loose plots. The channel has to leave well 1, reach well 2 before well 3, and finish on well 4, and there is only one way to join the pieces that does all three. The six missing links fall into place:

Notice the stretch from well 2 to well 3. The wells are neighbors, but the fence forces the channel the long way round, through the bottom-left of the field: eight plots counting both wells. The checkerboard explains why it could never have been seven or nine — see technique 4.

Seven techniques, from first look to last plot

1. Corners are forced

A corner plot has only two neighbors. Unless it is well 1 or the last well, the channel must come in through one and leave through the other, so you can draw both links at once. Do this for all four corners before anything else.

2. Fences make more forced plots

Every fence removes a side. A plot on the edge of the field with a fence beside it, or a plot in the middle with two fences, is often left with exactly two open sides — and then it is forced exactly like a corner. Sweep the whole field for these; in the example above they gave more links than the corners did.

3. A plot with one way in is an end

If a plot has only one open side, the channel can enter it but never leave, so it must be well 1 or the last well. The same logic works mid-solve: if your channel would leave an unwatered plot with only one open neighbor, and that plot is not the last well, the channel is already wrong. Erase back before that happens.

4. The checkerboard rule

Shade the field like a chessboard. Every step of the channel moves to a plot of the other shade, so the shades alternate all the way along. That gives you a counting check on every stretch between two wells:

• If two consecutive wells are on the same shade, the stretch between them waters an odd number of plots, counting both wells.
• If they are on different shades, it waters an even number.

In the example, wells 1 and 2 are both on shaded plots and the channel between them waters 9 plots; wells 2 and 3 are on different shades and the channel waters 8. When a route you are planning between two wells has the wrong count, it is wrong, and you know it before you draw it. The rule scales to the whole field too: on a field with an odd number of plots, such as 5 × 5 or 7 × 7, the channel starts and ends on the shade that has one more plot.

5. Never split the field

If your channel cuts the unwatered plots into two separate pockets, it can only ever reach one of them. Before you commit to a line along the middle of the field, check that everything on both sides is still connected to where the channel is heading.

6. Bottlenecks hold the end

Look for pockets of plots that connect to the rest of the field through a single gap. Once the channel enters such a pocket it cannot come back out, so the pocket must contain the last well, and the channel must fill it completely. A pocket with exactly two gaps must be entered through one and left through the other — and that usually tells you which way the channel runs through it.

7. Work backwards from the last well

The channel is the same whether you think of it from well 1 forwards or from the last well backwards. The last well has only one link, and its neighbors are often hemmed in by fences or the edge. Reasoning from both ends at once leaves a shorter gap in the middle to solve.

The Daily field: what changes through the week

Every day brings one new field, and everyone who plays on that date gets the same one; the game numbers them from Rill #1 on September 26, 2026. Like a newspaper puzzle, the field gets a notch harder towards the weekend:

Notice the trade-off. Thursday and Friday fields have the most wells, which makes them flow: each well is a waypoint that narrows the route. Weekend fields have fewer wells and more fences, so more of the work is forced-plot logic and counting.

The Ladder and its ranks

The Ladder is a sequence of levels that never ends, the same levels for every player. Fields grow slowly as you climb (4 × 4 from level 1, 5 × 5 from level 4, 6 × 6 from level 16, 7 × 7 from level 41, 8 × 7 from level 91), wells thin out, fences multiply, and from level 9 the generator only accepts fields that take its solver real effort. Ranks mark the way, and three of them unlock new looks for the field:

Blitz

Blitz is Rill against the clock. You start with 90 seconds and every solved field adds 7. The fields are small and grow as the run goes on (4 × 4 from field 1, 5 × 5 from field 4, 6 × 6 from field 15), so speed comes from recognising the forced plots at a glance rather than from thinking harder. In the iPhone app you can watch an optional ad once a run to add 20 seconds and keep going.

Streaks, hints and the share grid

Streaks. Solving the Daily on consecutive days builds your streak. Miss exactly one day and the game offers to restore it the next day: in the browser that is free once a week; in the iPhone app it costs a short optional ad.

Hints. You get 3 free hints a day. If your channel has already gone wrong, a hint rewinds it to the last correct plot; otherwise it reveals the next three plots of the solution. In the iPhone app, more hints are available by watching an ad.

The share grid. When you solve the Daily you can share a spoiler-free grid of squares, one per plot: 🟦 for a plot you watered cleanly, 🟨 for a plot you had to erase at some point, and 🟧 for a plot a hint revealed. Nobody can work out the answer from it, but everyone can see how clean your solve was.

Why every field is fair

Rill's fields are not drawn by hand and do not come from a server. Each one is generated on your own device from a seed — the date, for the Daily — by drawing a random channel through every plot, placing wells along it, and adding fences. A solver then searches the field for a second solution. If it finds one, the generator fences that route off or adds a well and checks again; if the field cannot be made unique, it is thrown away. Every field you see has exactly one answer, so there is never a second solution to stumble into. Because the seed for the Daily is the date, everyone's device builds the same field without any server involved.

That is also why Rill works offline once it has loaded, and why it never needs an account.