Japanese Notation (Garment Notation) displays abbreviated knitting instructions on a visual diagram of your garment piece. It can be used for increases, decreases or short row shaping.
Unless otherwise noted in your pattern, (not all designers use the same convention) the numbers are referring to stitches / rows /times
An instruction of 1-2-9 means (decrease, increase or hold) 1 stitch every 2 rows 9 times.
This example is from a pattern that is written in only 1 size
This example has multiple sizes and can be a bit confusing. The numbers in parenthesis (brackets) reflect alternate sizes.
The yellow highlighted instruction would read:
Size 1:
(1-9-4) Increase 1 stitch every 9 rows 4 times
Size 2:
(1-9-0) Increase 1 stitch every 9 rows 0 times
Size3:
(1-9-0) Increase 1 stitch every 9 rows 0 times
In other words, size 2 and 3 only use the first 3 lines of the shaping instructions.