Change Colour in Crochet Rounds.

Use two colours of the same smooth yarn and a comfortable hook. You also need a first-stitch marker, a second marker or contrasting yarn scrap, scissors and a blunt yarn needle. Name the lower colour A and the upper colour B.

For each spiral cup, work four single crochets into a magic ring in A. Mark the first stitch. Do not join or make a height chain between rounds.

Round two: work two single crochets in each stitch, giving eight. Round three: work one single crochet in the next stitch and two in the following stitch, repeating that pair four times. The eight old bases produce twelve new stitches.

Work rounds four and five with one single crochet in each stitch: twelve in each round. Move the first-stitch marker as each round begins. Secure the ring's starting tail through the fabric when you can inspect its route comfortably.

Stop the first cup one movement before completing round five's twelfth stitch. Insert into that final old base with A and draw up a loop, leaving two A working loops on the hook. The next section changes the colour during that stitch's final pull-through.

For the second cup, use the same setup and pause at the same point. These small cups are preparation for the colour-change exercises, not a general formula for a flat circle.

Place B over the hook, leaving a usable tail. Draw B through both A working loops to finish round five's twelfth stitch. One B active loop remains. The body of that completed stitch was made in A; the new colour is ready for the next stitch.

Insert into the marked first stitch of the previous round and make one complete single crochet with B. Move the first-stitch marker into this new B top. Continue with one B single crochet in each remaining base. There are twelve B single crochets in round six.

Work another spiral round of twelve B single crochets for round seven. Do not join or add a chain. Leave the working loop secured while you inspect the colour boundary.

The yarn changed at a defined stitch, but the fabric still follows a continuous rising path. Look for the height step near the change. Do not remove it by skipping the first B base or joining to a different stitch: those actions alter the construction or count.

Keep the A and B tails available for finishing. Snug a loose change gently without dragging a length of one colour through the neighbouring stitches.

On the second spiral cup, finish A round five's final stitch by drawing B through its two remaining working loops, just as in Sample A.

For the first B position of round six, insert under both top loops of the marked first old stitch. Yarn over with B and draw through the base and the active loop in one movement, making one slip stitch. Mark its new top immediately and leave it loose enough to enter on the next round.

Make ordinary B single crochet in the remaining eleven bases. The round has twelve occupied positions: one slip stitch and eleven single crochets. Do not add twelve single crochets after the slip stitch; that would create a thirteenth position.

Begin round seven by making one ordinary B single crochet into the marked slip-stitch top. Move the marker to that new single crochet. Continue with one single crochet in each of the next eleven tops, giving twelve single crochets in the new round.

The shallow first position can reduce the abrupt height change, but it also changes that position's stitch type. Compare the boundary and the feel of the fabric with Sample A rather than assuming the result must be invisible. If the slip stitch is too tight to enter, ease or remake it before continuing.

This substitution is the exercise's stated rule. A shaping round, a textured stitch pattern or a chart may require a different treatment. Use the method defined for the actual project instead of inserting a slip stitch wherever a colour changes.

Make a third cup in A. Start with four single crochets in a magic ring, then slip stitch into the first single crochet to close the round. That joining slip stitch does not count as one of the four.

Chain one without turning. Make the first single crochet of round two into the first actual old stitch, the stitch beneath the join. Make a second single crochet into that same base, then two single crochets into each of the remaining three bases: eight stitches. Join to the first new single crochet with a slip stitch.

For round three, chain one without turning. Work one single crochet in the first base and two in the next, repeating four times: twelve stitches. Join to the first new single crochet.

For rounds four and five, chain one without turning, make one single crochet in each of the twelve actual stitch tops and join to the first new single crochet. The chain and joining slip stitch stay outside the twelve-stitch count. Mark the first actual stitch so you can distinguish its top from the extra join.

Complete round five entirely in A, including its joining slip stitch. Fasten off A, keeping a tail for securing. This differs from the two spiral samples: you have closed the A round before starting B.

Put a slip knot of B on the hook, leaving a finishing tail. Insert beneath both top strands of the first actual A stitch. Yarn over with B and bring a loop through that base, giving two working loops. Yarn over and draw through both. This is the first B single crochet, made without an extra joining stitch or counted starting chain.

Mark its top. Work one B single crochet into each of the other eleven A stitch tops, then join to the first B single crochet with a slip stitch. Round six contains twelve single crochets.

For round seven, chain one without turning. Make one single crochet in the first actual stitch and each of the next eleven, then join to the first new single crochet. Again there are twelve stitches; do not work into the old joining slip stitch or the height chain.

This sample has a distinct round boundary and joining seam. A new-colour standing stitch avoids beginning B with a visible height chain, but it does not erase every sign of the join. Compare it as a different construction, not as the spiral with a single extra movement.

Before changing colour, check each cup: four stitches in round one, eight in round two, then twelve in each of rounds three, four and five. Count the tops around the current round; leave the join and height chain out of the joined cup’s count.

Sample A adds twelve single crochets in each B round. Sample B adds one slip stitch and eleven single crochets in round six, followed by twelve single crochets in round seven. Sample C adds twelve single crochets per B round plus uncounted closing joins and the stated uncounted height chain for continuing round seven.

Keep those stitch-type differences with your notes. Saying every sample has twelve positions in a B round is useful for placement, but it does not make the first B round identical in structure.

Inspect the outside and inside before securing the colour-change tails. Long loose spans can catch or pull the boundary out of shape. Finish each tail through the actual fabric using the weaving-ends guide, then check the boundary again after care suited to the yarn.

Use the round-construction guide to identify how a future pattern is built. If a change looks uneven, the colour-change troubleshooting guide helps separate a structural step from a missed stitch, a tight join or a loose tail. Choose the method that fits the pattern's counts and fabric rather than one that promises to hide every transition.