Amizu Japan

Mattress Stitch (Sukui-toji, すくいとじ): How Japanese Knitting Lessons Teach the Invisible Seam

Sukui-toji (すくいとじ) is the Japanese name for mattress stitch. See how Japanese lessons name and vary it, and how it compares with CYC's steps.

By Naruhiko (Naru) ·

Drafted in English with AI, from the sources listed at the end. How these guides are made.

On this page
  1. What both traditions agree on
  2. What Gosyo’s lessons add: a page for each case
  3. Reading “すくいとじ” in a pattern
  4. Garter stitch and crochet
  5. FAQ
  6. Sources

Short answer: Mattress stitch is called すくいとじ (sukui-toji) in Japan. The verb すくう (sukuu) means to scoop or pick up, and that is what you do: you pick up the horizontal “bar” between stitches, one row at a time, alternating from one side to the other, and pull the seam closed. The Craft Yarn Council’s English instructions describe the same pick-up. What stands out in Japanese lessons such as Gosyo’s is how many named variations they teach, depending on fabric and yarn.

Checked against Gosyo’s and Nihon Vogue’s lesson pages and the English guides below on 2026-10-18.

What both traditions agree on

The Craft Yarn Council (CYC) says, “One of the most common methods of seaming is Mattress Stitch,” and that it “is sometimes called ‘Invisible Seam’ because it almost disappears.” Its steps, in short:

  1. Thread a yarn needle with matching yarn and place the two edges side by side, right sides facing you.
  2. Start at the hem and secure the yarn through both sides. Pick up the bar between the first and second stitches on the right-hand side.
  3. Cross to the other side and pick up the bar there. Return to the right-hand side, put the needle into the same space it came out of, and pick up the next bar.
  4. After four or five stitches, tighten the yarn until it holds the seam firmly. Keep the rows matched.
  5. Continue up the seam, picking up every row bar.

Nimble Needles describes the same thing: go under the first bar between two knit stitches on the right piece, then under the first bar on the left piece, and move up one bar at a time on each side. It warns: “Don’t pull too tight. Otherwise, your seam will buckle!”

A Japanese lesson from Gosyo (ごしょう産業, a yarn company) starts at the cast-on edges with the cast-on tail, then describes the basic version in one line: 1目中の横糸を交互に1段ずつすくい、とじた糸は見えなくなる程度に引きます, “pick up the horizontal thread one stitch in, alternating one row at a time, and pull until the seaming thread can’t be seen.” Same method, same tension target.

What Gosyo’s lessons add: a page for each case

Gosyo’s seaming lessons separate the technique into named variants:

Japanese page titlePlain EnglishWhat the page says
メリヤス編みのすくいとじ＜１段ごと・1目中＞Stockinette, every row, one stitch inStart from the cast-on tails; pick up the horizontal thread one stitch in from the edge, alternating one row at a time
＜半目内側のすくいとじ＞ (same page)Half a stitch inFor 極太 (gokubuto) yarn and thicker: pick up the thread half a stitch in from the edge, so the seam allowance (とじ代, toji-shiro) does not get thick
表目２段ごとのすくいとじStockinette, two rows at a timeFor fabric finer than 中細 (chūboso) yarn makes, at side seams, sleeve seams and in colorwork: pick up two rows at once on each side, one stitch in from the edge. For 合太 (aibuto) up to about 極太, the page says to pick up one row at a time
裏目１段ごとのすくいとじReverse stockinette, every rowFor when the reverse-stockinette side is the right side: butt the edges together and, one stitch in, pick up the lower strand of the horizontal thread, alternating one row at a time; pulling a little tighter (少しきつめ) closes it neatly
１目ゴム編みのすくいとじ1x1 ribHave one edge end in one knit stitch and the other in two (the lesson index adds: knit the rib on an even number of stitches), then pick up alternately, row by row, as the page shows
コの字とじ“コ-shaped seam” (the katakana コ looks like a square bracket)Pick up the edge stitches in a コ shape; the page says it gives a thin seam and warns not to pull too hard

Instead of one tutorial with a list of caveats, Gosyo gives each fabric its own page.

Two points to notice:

  • “1目中” (hitome-naka) locates the pick-up point by counting stitches in from the edge. Gosyo’s other seaming pages put it in fuller words, 端から1目はいったところ (“one stitch in from the edge”), and the diagram on the basic page shows the needle under the bars one stitch in. Nihon Vogue’s basics page describes すくいとじ the same way: pick up the threads running across 1目内側や半目内側, one stitch or half a stitch in. That matches CYC’s “bar between first and second stitches.”
  • Tension changes with the fabric. Gosyo’s basic page says to pull until the thread is hidden, and its reverse-stockinette page says to pull a little tighter (少しきつめ). CYC says to tighten after four or five stitches until the yarn holds the seam firmly. “How tight” depends on the fabric, so a swatch is your friend.

Reading “すくいとじ” in a pattern

Gosyo’s lessons define the two families outright. Its とじ (toji) lessons open with 編み地の段と段をつなぎ合わせることを[とじる]といいます, “joining rows to rows is called tojiru,” and its はぎ (hagi) lessons with 編地の目と目をつなぎあわせることを[はぎ]といいます, “joining stitches to stitches is called hagi.” So when a Japanese pattern’s finishing notes say すくいとじ, it means seaming row edges together; Gosyo’s two-row page names side seams (脇, waki) and sleeve seams (袖下, sodeshita). Look at the notes for:

  • Which fabric the edge is: メリヤス (stockinette), 裏メリヤス (reverse stockinette), or ゴム編み (rib).
  • Whether it asks for 1段ごと (every row) or 2段ごと (every two rows).
  • Whether it names 半目内側 for thicker yarns.

There is no chart symbol for a seam. JIS L 0201, the Japanese standard for knitting stitch symbols, covers the stitches themselves and has no symbol for はぎ or とじ (see how to read a Japanese knitting chart). Patterns name the seam in words instead, on the schematic or in the finishing notes (仕上げ方).

For stitch-to-stitch joins, see Kitchener stitch, the Japanese way. Gosyo’s はぎ pages add that a はぎ can also join stitches to rows (目と段の場合もあります).

Garter stitch and crochet

Garter stitch needs a variation. Nimble Needles says the classic technique “only works for stockinette stitch” and gives a garter version in a separate tutorial. Each garter ridge has two bumps, “offset by half a row, so you have a top bump and a bottom bump,” and the seam goes through those bumps at the edge of each piece, alternating top and bottom.

The CYC also has a crochet seaming page. With the needle pointing up, you pick up the corresponding row on the opposite piece, then a stitch on the first side, and “Tighten yarn in seam after picking up 3 or 4 stitches.” It adds: “Yarn must be tight to disappear, but not enough to shorten seam.”

FAQ

Is すくいとじ exactly the same as mattress stitch? It is the same kind of seam: row edges joined by picking up the horizontal bars. Japanese lessons such as Gosyo’s divide it into named cases by fabric and yarn weight.

Why does my seam pucker? Pulling the yarn too tight can do it. Nihon Vogue’s basics page says to pull until the thread disappears, but warns that pulling too hard makes the seam pucker (引きすぎるととじた位置がつれます), so balance it against the stretch of the fabric. Nimble Needles warns that the seam “will buckle,” and CYC’s crochet seaming page says the yarn “must be tight to disappear, but not enough to shorten seam.”

What does “半目内側” mean? Half a stitch inside the edge. Gosyo gives it for 極太 yarn and thicker, to keep the seam allowance from getting bulky.

Is there a different seam for ribbing? Gosyo has a page for 1x1 rib (１目ゴム編みのすくいとじ), with the edge-stitch setup described above.

How tight should I pull? Until the seaming thread disappears (Gosyo) and holds the seam firmly (CYC). Gosyo says to pull a little tighter in reverse stockinette. Swatch first.

Sources

All pages below were opened on 2026-10-18.