Crochet Pattern: Diagonal Box Stitch Square (Mystery Lapghan CAL)

Last month, I shared the Diagonal Rainbows Baby Blanket pattern with you. I had so much fun using this variation of the diagonal box stitch (also known as the corner-to-corner or c2c technique), that I decided to design a 6″ (15 cm) square using it.

This square is my first contribution to the Mystery Lapghan Crochet-a-long, a fun crochet event featuring 36 6″ (15 cm) squares by 30 crochet designers.

Diagonal Box Stitch Square, free 6" (15 cm) crochet pattern with video tutorial by Marie Segares @ucrafter. Part of the Mystery Lapghan CAL 2015 - 36 free crochet patterns for 6" squares!

This post contains affiliate linksThe yarn for the sample was generously provided by Lion Brand.

Mystery Lapghan Crochet-a-long featuring 29 #crochet designers and 36 free patterns for 6" (15 cm) squares. Join the Facebook group at

You can read more about the CAL here, or join the Facebook group to chat with participating crocheters.

The great thing about using this pattern for the CAL is that it can easily be adjusted to match your specific gauge. I included a video tutorial at the bottom of the post in case you are new to corner-to-corner crocheting. I used different hook sizes for the sample square pictured above and the one in the video, and each required a different number of rows to reach the same size. You can make similar adjustments to your own square!

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Featured Five Club

Diagonal Box Stitch Square

Crochet Pattern by Underground Crafter

02-easy 50
US terms 50
4-medium 50

A variation on the diagonal box stitch.

Finished Size

  • Adjustable. Photographed sample is 6” (15 cm) square.


  • Lion Brand Heartland yarn (100% acrylic, 3.5 oz/100 g, 170 yd/156 m) – 1 skein each in 169 Shenandoah (CA) and 109 Olympic (CB), or approximately 30 yds (27 m) each in CA and CB in any medium weight yarn.
  • US Size I-9/5.5 mm crochet hook, or any size needed to obtain gauge.
  • Yarn needle.


  • Finished Square = 6” (15 cm) in pattern. Exact gauge is not critical for this project.

Abbreviations Used in This Pattern

  • BL – back loop only
  • CA – Color A
  • CB – Color B
  • ch – chain
  • dc – double crochet
  • ea – each
  • rep – repeat
  • Rnd(s) – Round(s)
  • sc – single crochet
  • sk – skip
  • sl st – slip stitch
  • sp – space
  • st(s) – stitch(es)
  • yo – yarn over
  • * Rep instructions after asterisk as indicated.

Pattern Notes

  • Square is crocheted in one piece in rows from corner to corner using a variation of the diagonal box stitch.
  • Stitch pattern is reversible, so choose best side as right (front) side before joining to other squares
  • To adjust size, continue repeating Row 3 until straight edge reaches your desired length.
  • A video tutorial for this pattern is available below. Scroll down for the written pattern.
  • If you can’t see the video for the Diagonal Box Stitch Square above, click here to watch it on YouTube.

Pattern Instructions

  • With CA, ch 5.
  • Row 1: Turn, sk 3 (counts as ch-3 sp), dc in next 2 ch. (1 box)
  • Row 2: Ch 5, turn, sk 3 sts, dc in next 2 st, (sl st, ch 3, 2 dc) in ch-3 sp of previous row. (2 boxes)

Increase to center

  • Row 3: Ch 5, turn, sk 3 sts, dc in next 2 st, *(sl st, ch 3, 2 dc) in next ch-3 sp of previous row; rep from * across. (Increases by 1 box ea row)
  • Rows 4-8: Rep Row 3, 5 times.
  • Row 9: Rep Row 3, changing to CB in last yo of final st of row. Fasten off CA.

Decrease to end

  • Row 10: Turn, sl st in first 2 sts, *(sl st, ch 3, 2 dc) in next ch-3 sp of previous row; rep from * across to last ch-3 sp, sl st in ch-3 sp. (Decreases by 1 box ea row)
  • Rows 11-16: Rep Row 10, 6 times.
  • Row 17: Rep Row 10. Fasten off CB.


  • With yarn needle, weave in ends. Spray block if necessary.
© 2015 by Marie Segares (Underground Crafter). This pattern is for personal use only. You may use the pattern to make unlimited items for yourself, for charity, or to give as gifts. You may sell items you personally make by hand from this pattern. Do not violate Marie’s copyright by distributing this pattern or the photos in any form, including but not limited to scanning, photocopying, emailing, or posting on a website or internet discussion group. If you want to share the pattern, point your friends to this link: Thanks for supporting indie designers!

41 thoughts on “Crochet Pattern: Diagonal Box Stitch Square (Mystery Lapghan CAL)”

  1. I have been seeing this technique around a lot lately, and I am really liking the look of the pattern. I definitely need to give it a try, and what a more perfect time, than as part of the mystery lapghan?!

    • Carmen, there isn’t such a document. What I’ve noticed in the Facebook group is that some people are using scraps and others have 3 or 4 colors they are using for each square. I’ve found that most 6″ squares use less than 60 yards of yarn, so I think it is a good amount to guestimate for each square.

  2. Thank you for the video! I too have been seeing the C2C, mostly in blankets, and thought a CAL was the way to try it, but somehow I wasn’t managing to “get it” from the written instructions. I never look at crochet or knitting videos, but I’m glad I tried this one – and I’m very proud of my completed 6″ square! I’m sure it’s not the last instructional video I’ll check out now 😀

  3. Am I the only person who gets an error saying content is unavailable whenever I click on any link for the Facebook group for the Mystery Group CAL? If so, why?

  4. I used this pattern years ago to make an afghan in my sons high school colors (1985)! But it took me nearly 8 years to finish it!! I made 80 squares with royal blue on one corner, white in the middle and steel silver grey on the other corner. Sewing it all together was the hardest part. In fact my sister-in-law finished sewing the last half together as I had some health issues that kept me from working on it and it was stored away for some time. I had the pattern for one done in red, white and blue. It goes together with like colors touching and it looks like large blocks of blue and grey framed in with wide rows of white. I’ll try to get a picture taken and put in my computer so you can send me an email request for here. I’m on Facebook but don’t have any pictures of some of my crocheted projects I’ve done. I’m 71 and have crocheted since I was nine when my sister taught me to make a chain till I got all the stiches the same size!! Enjoyed the tutorials here on this site. Thank You.

  5. Thank you very much for putting this out. Looked at several other instruction sets before I found this and your pattern is the clearest to follow. As someone who is self taught with tutorials, this clarity is extremely helpful. Thanks again.


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