Increase and Decrease in Tunisian Simple Stitch.

Make two small Tunisian simple-stitch samples, each with nine positions and at least two completed rows above its setup. Use the standard return pass and ordinary two-strand final edge. Keep the same face towards you.

Use one sample for each exercise. Do not apply the nine-position instructions to a row you have already increased or decreased. Alternatively, undo the exercise row completely before trying the other method.

The active loop at the start of each forward pass already represents the first edge position. You will work seven interior positions and the final edge in a plain nine-position row.

For this exercise, work three ordinary interior Tss after the retained first edge. You now have four loops on the hook.

Find the gap between the stitch just worked and the next stitch:

1. Insert the hook through that gap from front to back.
2. Catch the working yarn behind the fabric and draw a loop to the front.
3. Keep the new loop on the hook, leaving the next stitch's front bar unused for now.

That is the increase. You have added a loop without using the next stitch's front vertical bar.

Now work that next stitch normally and continue through the remaining interior bars. Work the final edge beneath both strands of its outside V.

Count ten loops before starting the return. You have kept both edges and all seven original interior positions, then added one pickup in the gap.

Complete the standard return pass. Its first pull-through-one leaves ten loops on the shaft, then nine pull-through-two movements reduce the total to one.

The added loop forms a new stitch column when the return pass is completed. Identify its front vertical strand between the neighbouring original columns before making the next forward pass.

Work one plain Tss row across the new ten-position width, including that added column once. The count is one retained first edge, eight interior pickups and one final edge: ten loops.

Do not add another loop in the gap on this plain row. Repeating the increase unintentionally would add another position. The appearance and size of the opening depend on the method and tension, so compare the actual sample rather than calling this a hole-free increase.

Return to the separate nine-position sample. Begin its forward pass with the retained edge, then work two ordinary interior Tss. There are three loops on the hook.

At the next two interior stitches:

1. Pass the hook beneath the front vertical bar of the first stitch and then beneath the next stitch's front vertical bar.
2. Do not draw up a separate loop between those insertions.
3. Yarn over and draw one new loop through both gathered bars.
4. Retain that one new loop on the hook.

This Tss2tog uses two existing positions and adds only one loop. Work the remaining three interior stitches normally, then work the final edge.

Count eight loops: one retained edge, two ordinary pickups, one shared pickup, three ordinary pickups and one final edge.

Complete the standard return pass, then make a plain eight-position row if you want to inspect the new width. Find the single new front bar above the decrease and work it once; do not work into both old bars below it as extra positions.

Both exercises place the shaping in the interior so you can keep the starting and final edges consistent. An accidental extra pickup at the first edge can cancel a decrease numerically while leaving the shaping in the wrong place.

A skipped stitch and two bars gathered together are not identical constructions. A yarn-over increase also produces a different insertion and appearance from the gap pickup used here. Follow the named method and definition in the actual pattern.

After the final return pass of each sample, use the defined simple-stitch slip-stitch bind-off across the remaining positions, including the final edge, then fasten off and secure the tails. The ten-position sample has nine remaining bind-off positions after the retained first edge; the eight-position sample has seven. Keep the bind-off relaxed so it does not create a narrower top edge.

Label the original width, shaping location, new forward-loop count and method on each sample. These are movement exercises, not a fitted shape or a promise about finished dimensions.

Use the gauge guide when a project needs measured shaping. Follow the blocking and care lesson alongside the yarn label, and use the counter only after checking the actual loops.