STEP 9: Heel Extension
!!!Let Sock 2 hang on the cable while you work the entire heel extension and heel flap back and forth on Sock 1. Then you will work the heel extension and flap on Sock 2 while Sock 1 waits!!!
There will be _____ stitches (Chart 1, Row J) still unworked. (The H+I stitches will be worked back and forth in short rows until the heel flap. The G and J stitches on either side just hang out and wait.)
Repeat Rows 1 & 2 until _____ stitches (Chart 1, Row K) remain that are being knit with reinforcing thread, ending with a wrong-side row.
At this point, you can get rid of this marker, too. Even if you're not using reinforcing thread, you'll have no problem seeing the stitches to knit for the extension because—as you can see from the next picture—the gaps will leave no doubt about when to stop and turn:
and are ready to begin the Heel Flap on a RS row.
Workshop: MUMTU Socks Pt8:
the socks for sleeping, they don't need reinforced.
At this point, you have just completed your last row (a WS row)