More confusing directions

Working on a new pattern, I have these directions I don’t get: “begin chart … repeating full chart for rest of back, while at the same time decrease 1 st on each side every 10 rows, 3 times …” It’s the “on each side” I don’t get - is that RS/WS, or does it mean at the end of the row (and why not say that!?)

any help most appreciated!

AMC

If you could post a link to the pattern it might help us determine exactly what is expected of you. Not having that, I would say that every 10th row you are decreasing one stitch on each END of your work on that particular row for a total decrease of 9 stitches over all.

You do a decrease at each end of rows 10, 20 & 30. So if this is the RS, you ssk at start & k2tog at the end.

If the chart isn’t marked for the decreases, remember to compensate by ignoring the first stitch each side rows 11-20. The first & last 2 stitches, rows 21-30. And the first & last 3 stitches, rows 31 on.