The Baby Surprise Jacket was designed by Elizabeth Zimmermann in 1968 and remains a popular baby garment to this day. It is an excellent pattern for making use of oddments of yarn or self striping yarns with long colour repeats, but looks equally nice knit in a single colour with a contrasting button band.
The jacket is knit in a single piece with just two seams that run across each of the shoulders and down the length of the sleeves. It includes extra ease across the back of the garment to fit well over a nappy (diaper).
Commonly referred to as the “BSJ”, the baby surprise jacket is a very entertaining piece of knitted engineering.
A completed baby surprise jacket
When you first cast off your BSJ it will look like something like this. Do not fear! This is what it is supposed to look like!


When folded according to the pattern, it magically reshapes itself into a very normal looking baby jacket.


Notes on the Pattern
Gauge and Size
16 stitches per 4”/10cm = 22 ½” chest circumference
20 stitches per 4”/10cm = 18” chest circumference
22 stitches per 4”/10cm = 16 ½” chest circumference
24 stitches per 4”/10cm = 15” chest circumference
28 stitches per 4”/10cm = 13” chest circumference
Minor Pattern Changes
Avoiding picking up stitches on the wrong side of the row

I used the instructions from Knitting Workshop to knit my BSJ and there is a minor change in the order of the knitting that I will make next time. In the section where the pattern says to work 10 ridges on the centre 90 sts and then pick up stitches and knit to the end, I work this as follows:
Having finished after working a wrong side row, break the yarn. With right side facing rejoin the yarn at the first marked stitch and work 10 ridges on the centre 90 sts, ending having just worked a wrong side row. Break the yarn.
Rejoin the yarn to the very beginning of the row. Knit 34, pick up 10 stitches along the side of the centre panel that you have just knit, knit across the centre 90 stitches, pick up 10 stitches down the other side of the centre panel and knit the final 34 stitches. Turn and knit back across the entire row.
You now have 178 stitches and can continue with the pattern where it says “(178sts)”. Working the centre in this manner means you won’t have to pick up any stitches on the wrong side of your knitting, the front edges will match exactly and you will be able to work stripes wherever you wish.
Casting off

Continue working your increases on the cast off row to keep the bottom corner of the button bands from becoming rounded.
Placing Your Stripes
The following is a short guide to where the stripes will fall as you knit.

This photo shows my BSJ at 22 ridges. Stripes worked in this section fall across the ends of the sleeves and across the full width of the back

This photo shows my BSJ after working the neck shaping. Stripes worked here will fall down the front of the jacket and across the hips.
Lengthening the Sleeves
There are many ways to lengthen the sleeves on a baby surprise jacket. Blouson Sleeves

To knit a BSJ with longer sleeves you will need to cast on using a long tail cast on. This will make the ridge where you pick up the stitches to lengthen your sleeves totally invisible on the right side of the knitting.
Cast on an extra 9 stitches on each side (a total of 178sts) and place your first marker on the 45th stitch. Place your second marker on the 134th stitch.
Row one will begin and end with k43
Row three will begin and end with k42
Row five will begin and end with k41 and so on.
When the pattern says to increase 9 sts across the end sections just knit without increasing as you already have the extra 9 stitches in place. Continue knitting the pattern as written.
When you have finished knitting the jacket as written in the pattern (including casting off), pick up 44 stitches along the end of your sleeve and knit 10 rows.
Next row: K2, *K2tog, k1; repeat from * to the end of the row (30sts)
Change to needles one size smaller than those you used to knit the rest of your baby surprise jacket and work 14 rows k1, p1, rib. Cast off and sew up your jacket.
Collars
Fold-Over Collar

After sewing the shoulder seams, with the right side facing you, pick up 18sts along the front edge of the neck, up to the shoulder seam, 17 stitches across the back and 18 stitches down the other side of the front.
Knit 8 ridges (15 rows) and cast off. For a deeper collar just knit more rows before casting off.
Shirt Collar
You can find directions for adding a shirt collar to your BSJ on Panda Man’s Knitting Corner blog.
Big Mitred Collar

After sewing the shoulder seams, with the right side facing you, pick up 17sts along the front edge of the neck, up to the shoulder seam, 18 stitches across the back and 17 stitches down the other side of the front. (52sts)
Knit one row.
Mark the 13th and 40th stitches.
1st row: Knit, working M1 at both sides of each marked stitch.
2nd row: Knit
Repeat the last 2 rows until you have worked 10 ridges (19 rows). Cast off, working the increases on the cast off row so the points on the collar remain sharp.
Adding a Hood
Instructions for adding a hood to the BSJ can be found in the letters section in Knitters Magazine #57, Winter 1999
Sophia of the Yarn Over Manhattan blog has used the Tomten hood on a BSJ to very nice effect.
Stella of knitknitfrog has also added a hood based on EZ’s mitered baby bonnet pattern which is available in the Opinionated knitter. The mitered bonnet follows the mitering of the original BSJ, and the jacket was finished with an i-cord.The interesting dots where the stripes change colors was achieved quite simply by starting all stripes on the right side of the work, then knitting the first row a strip with alternate stitches in the old stripe colour and then the new stripe colour. Following rows are knit to continue the garter stitch effect.

Different effects occur depending on how stripes are placed when working the back section of the hood.

This hood was mattress seamed to the neck, but possibly could be reverse engineered so stitches were picked up around the neck and the hood knit up.
Adding a Ruffled Edge and Cuffs

Ravelry user loves2knit4six has added a ruffled edge and cuffs to her BSJ using an adaptation of the edging on Jillian Moreno’s Boo coat on knitty.com
Working the Jacket in Stockinette or Stocking Stitch
You can find a full list of changes to the pattern on the “Panda Man’s Knitting Corner” blog. Please note that you will still need the original pattern in order to use these changes.
Where to Find the Pattern
Knitters Magazine Spring 1989 pp 26-27, ‘The Original Baby Surprise Jacket’
Knitting Workshop by Elizabeth Zimmermann
Knitting the Baby Surprise Jacket DVD includes instructions for knitting a collar and matching bonnet
The Opinionated Knitter by Elizabeth Zimmermann. The Opinionated Knitter also contains patterns for a matching bonnet, booties and a bunting bag.
Spun Out 1B from Schoolhouse Press
Vogue Knitting International Spring/Summer 2007 pp 28, EZ’s Surplice Baby Jacket (a BSJ with surplice styling)