Squares on paper, diagonals in your hands
Corner-to-corner crochet builds a fabric out of small tiles called blocks. Instead of working in horizontal rows, you start with a single block in one corner and work outward in diagonal rows, each one a block longer than the last. The finished piece is a rectangle, but every row runs at 45 degrees.
A C2C graph is a grid where every square is one block. You read it the same way you work it: along the diagonals. If you tilt the graph so the starting corner points towards you, the diagonals become horizontal lines, which some people find easier to follow.
The size of a graph
The number of diagonal rows equals the width plus the height minus one. A 60 × 60 graph has 119 diagonals; a 60 × 40 graph has 99. That is useful to know when planning how long a project will take, and it explains why C2C feels fast at the start and the end, when the diagonals are short, and slower in the middle:
- Diagonal rows
- 9960 + 40 − 1 for a 60 × 40 graph
- Longest row
- 40 blocksrows 40 to 60
- Done after a quarter of the rows
- 13.5%of the 2,400 blocks
- Done at the halfway row
- 50.8%the middle rows are the long ones
Why C2C feels fast, then slow, then fast
Blocks in each diagonal row of a 60 × 40 graph
Show the numbers
| Diagonal row | Blocks in the row |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 3 |
| 4 | 4 |
| 5 | 5 |
| 6 | 6 |
| 7 | 7 |
| 8 | 8 |
| 9 | 9 |
| 10 | 10 |
| 11 | 11 |
| 12 | 12 |
| 13 | 13 |
| 14 | 14 |
| 15 | 15 |
| 16 | 16 |
| 17 | 17 |
| 18 | 18 |
| 19 | 19 |
| 20 | 20 |
| 21 | 21 |
| 22 | 22 |
| 23 | 23 |
| 24 | 24 |
| 25 | 25 |
| 26 | 26 |
| 27 | 27 |
| 28 | 28 |
| 29 | 29 |
| 30 | 30 |
| 31 | 31 |
| 32 | 32 |
| 33 | 33 |
| 34 | 34 |
| 35 | 35 |
| 36 | 36 |
| 37 | 37 |
| 38 | 38 |
| 39 | 39 |
| 40 | 40 |
| 41 | 40 |
| 42 | 40 |
| 43 | 40 |
| 44 | 40 |
| 45 | 40 |
| 46 | 40 |
| 47 | 40 |
| 48 | 40 |
| 49 | 40 |
| 50 | 40 |
| 51 | 40 |
| 52 | 40 |
| 53 | 40 |
| 54 | 40 |
| 55 | 40 |
| 56 | 40 |
| 57 | 40 |
| 58 | 40 |
| 59 | 40 |
| 60 | 40 |
| 61 | 39 |
| 62 | 38 |
| 63 | 37 |
| 64 | 36 |
| 65 | 35 |
| 66 | 34 |
| 67 | 33 |
| 68 | 32 |
| 69 | 31 |
| 70 | 30 |
| 71 | 29 |
| 72 | 28 |
| 73 | 27 |
| 74 | 26 |
| 75 | 25 |
| 76 | 24 |
| 77 | 23 |
| 78 | 22 |
| 79 | 21 |
| 80 | 20 |
| 81 | 19 |
| 82 | 18 |
| 83 | 17 |
| 84 | 16 |
| 85 | 15 |
| 86 | 14 |
| 87 | 13 |
| 88 | 12 |
| 89 | 11 |
| 90 | 10 |
| 91 | 9 |
| 92 | 8 |
| 93 | 7 |
| 94 | 6 |
| 95 | 5 |
| 96 | 4 |
| 97 | 3 |
| 98 | 2 |
| 99 | 1 |
Working the diagonals
CraftPatterns written instructions start at the bottom right corner and alternate direction on each row, exactly as you work back and forth.
- Diagonal 1 is the single block in the corner.
- Diagonal 2 has two blocks: you turn, add a new block, and attach to the first.
- Diagonal 3 has three, and so on.
Increasing
While both edges of your work are still inside the graph, every diagonal begins with an increase (a new block started from a fresh chain) and ends by attaching to the last block of the previous row. Your piece grows as a triangle with two straight edges.
When one side reaches its edge
On a rectangle, one edge reaches the side of the graph before the other. Say your graph is 60 blocks wide and 40 tall, and you start at the bottom right. After 40 diagonals the work has reached the full height on one side. From then on:
- on that side, you decrease: instead of starting a new block, you slip stitch along to the next chain space and continue.
- on the other side, you keep increasing as before.
The diagonals stay the same length during this middle stretch, because you add a block at one end and remove one at the other.
Decreasing to the final corner
Once both edges have reached the sides of the graph, you decrease at both ends of every diagonal. The rows get shorter and shorter until you finish with a single block in the opposite corner.
| Phase | Start of row | End of row | Row length |
|---|---|---|---|
| Growing | Increase | Increase | One block longer each time |
| Middle (rectangles only) | Increase on the long side | Decrease on the short side | Stays the same |
| Shrinking | Decrease | Decrease | One block shorter each time |
Reading colours on a diagonal
Each written row lists the colours in the order you meet them, such as a few blocks of a background colour, a run of a design colour, then background again. Following the written row is usually faster than counting squares on the graph, but keep the graph nearby to sanity-check where you are.
On the graph itself, run a ruler or a strip of card along the current diagonal. Many crocheters use a highlighter on a printed copy to cross off each finished diagonal. On a tablet, the stitch tracker outlines the current diagonal row, numbered as in the PDF; step to the next row with its arrow buttons, mark the whole row done with one tap, and see how much of each colour is left.
Making a colour change
The neat way to switch colour is to change on the last yarn over of the block before the change, so the new colour is already on your hook when the new block starts. This avoids a stray loop of the old colour showing on the front.
Managing several colours
| Method | Best for | Trade-off |
|---|---|---|
| Separate bobbins per area | Large, separate patches of colour | More bobbins to untangle |
| Carry the yarn inside the blocks | Short gaps between blocks of the same colour | Can show through with light colours |
| Cut and weave in | Single isolated blocks | More ends to finish |
Graphs with lots of single blocks of a colour scattered around are hard work in C2C, because each one may mean a separate bobbin or a cut end. When you create a pattern in the C2C pattern generator, raising confetti cleanup and keeping the colour count modest makes a noticeable difference. The default of 8 colours suits many photos; bold graphics can often use fewer.
Choosing yarn colours
C2C patterns on CraftPatterns use a set of 48 named generic yarn shades, such as “Pumpkin” or “Deep Teal”, rather than a specific yarn brand, because yarn ranges vary so much. Treat the names as a description of the colour you are looking for, then find the nearest shade in the yarn you plan to buy. If you prefer exact codes, DMC® thread colours can be used as a colour reference instead.
Whatever you buy, keep all the yarn for one colour from the same dye lot if possible, and check your colours side by side in daylight. Two shades that look distinct on screen can be closer than expected in real yarn.
Estimating yarn
Yarn use is roughly the number of blocks times the yarn each block takes. With the default setting of 0.9 m per block, a 60 × 40 blanket of 2,400 blocks needs about 2,160 m in total, shared between its colours in proportion to their block counts. That default is on the generous side: published worsted patterns work out nearer 0.7 to 0.8 m per block, so the margin covers joins, tails and tension differences. The colour key gives a figure for each colour.
To get a figure for your own yarn and hook, crochet a test swatch of a few blocks, measure the yarn one block uses, and enter that in the yarn per block setting. Many crocheters then add a little extra for joins, tails and the border.
Text and borders
C2C works beautifully for names and short words on blankets and cushions. The C2C text generator builds a lettered graph with an optional border, and its written rows follow the same diagonal order as photo patterns, so you can read them in exactly the way described above.