Snap a Line!

Mudejar carpenters of Teruel Cathedral, Aragon, Spain, 12th-16th c.

When I was 7 my father called me out to the patio to help him as he was building a bookcase. He told me to hold a string to the end of a board, hold it tight and don’t let go. He snapped the string, there was a mini-explosion of dust and a blue line appeared on the board. My reaction was something like this:

So, you might not be surprised I have a collection of line snaps.

It’s Ancient

What I find appealing about snapping a line (besides the magic blue line) is it is an ancient method used by carpenters, masons and artists. It is not complicated and it works. Ancient Egyptians used red and yellow ochres and black inks for their lines. We can still see traces of the lines used on wall paintings to divide panels and keep figures in alignment.

Tomb of Horemheb, Saqqara, 18th Dynasty, 1319-1292 B.C.

One of the folktales about Lu Ban, legendary carpenter of China (born around 500 B.C.), is about how he taught stone masons the use of the ink line marker. It is said the ink marker was one of the tools he always carried with him.

Lu Ban snapping a line.

It’s Biblical

Isaiah 44:13: The carpenter stretcheth out his rule; he marketh it out with a line…

Construction of Noah’s Ark, Northern Italy, ca. 1300.

Although we can’t see what kind of marking tool is used, the carpenters in the third row down on the left are about to snap a line.

Hours of Catherine of Cleves (MS M.917, 105r), Utrech, ca. 1440, Morgan Library.

This is captioned as “Solomon observing the measuring of the timber.” We know the carpenter is going to snap a line.

Detail from the restored Construction of Noah’s Arc, fresco by Piero di Puccio, Camposanto di Pisa, 14th century.

In this Ark scene it appears a line will be cut at an angle across the board rather than the board’s length. The ink pot is near the foot of the carpenter in blue.

Engraving of the painting known as The Raboteur, attributed to Annibale Carracci, late 16th or early 17th century.

It probably isn’t too far off the mark to state most of the line snapping in the New Testament is to be found in scenes of Jesus helping his Joseph. Here again, only the line can be seen.

It’s Universal

The scenes on the left and top right are from various sections of the “Lu ban jing” written around 1600. On the left a line is about to be snapped; at the top right the carpenter’s modou is on the ground (look for the wheel). On the bottom left is a Korean carpenter with his line marker positioned with his other tools. The artist is Kim Jun-geun, who documented many tradesmen in a vernacular style (late 19th to early 20th century).

In the foreground the older carpenter holds the sumitsubo and is about to snap the line as the apprentice holds the end.

Portion of the scroll Kasuga Gongen Kenki Emaki by Takashina Takakane, ca. 1309.

This scroll was made using paint and ink on silk. It shows consecutive tasks: marking a log to be split, snapping a line on a board to be cut or split, carpenters sitting on a board and splitting it in two.

Processing beams for use in mines, France, 1529, BnF.

In the middle of the scene the inked line has been stretched and the square ink box is nearby on the ground.

Both of these images are 16th century German. On the left the line has been pulled from the ink box, on the right the reel with wound-up line is on the ground with a round ink pot(?) to the right.

Tools: Rotating Spindles to Chalk-O-Matic

Left: Ancient Egyptian mason’s line, Middle Kingdom tomb at Deir el Bahri. Right: carpenters, Madras, India, ca. 1785, V&A Museum.

The mason’s line has a rotating spindle and bears a strong resemblance to the spindle held by the Indian carpenter (top left in the painting).

From ‘Ancient Carpenter Tools’ by Henry C. Mercer.

The majority of the spools and reels shown were types used in Europe and the Americas. The one outlier is the Korean line marker (bottom right) from Kangkei (now known as Kanggye). Note: Henry Mercer wrote “twanged.”

The Japanese sumitsubo is still used today (as are more modern line markers). The 20th century Stanley chalk line with the very American name “Chalk-O-Matic” is still found in many a tool box.

As the handle on the sumitsubo is turned, string unwinds from the wheel and is pulled over ink-soaked cotton wool in the bowl and exits through the hole on the end. Chalk is enclosed in the Chalk-O-Matic and as the string is pulled out it gets a nice coating of blue chalk and basically works the same as the sumistubo.

My favorites: on the left a beautifully scaled fish sumitsubo; top right is a Chinese shipwright’s mondou (from the book “China at Work” by Hommel), bottom right is another boat-shaped sumitsubo (Skinner Auctions).

Woodblock, Edo Period, Harvard Art Museum.

The Japanese sumitsubo and try square are often pictured together in woodblock prints. And there’s a reason for that.

Taking another look at a detail in the Takashina Takakane scroll you can see both carpenters in the foreground are using a sumitsubo and a square as a plumb-line.

Suzuki, Masaharu, 1874 in “Wood and Wood Joints: Building Traditions of Europe, Japan and China” by Klaus Zwerger.

Another illustration of how the two tools are used together as a plumb-line.

Back to Antiquity

Ancient Greek carpenters also used snap lines (of course they did). They used red and black lines. Although I don’t have an image there is a passage from “The Greek Anthology” by W.R. Paton in 1916 that you might like to read (a translation of the Anthologia Palatina). Numbers 204 and 205 are by Leonides of Tarentum, a poet from the 3rd century B.C.  Click on the image to make it easier to read in either Greek or English.

The gallery has a few more selections.

Suzanne Ellison

This entry was posted in Asian Woodworking, Historical Images, Personal Favorites. Bookmark the permalink.

40 Responses to Snap a Line!

  1. Andrew Brant says:

    So great! I love these kind of posts.


  2. Maurice says:

    Bravo Suzanne ! Superbes ces images sur la manière de battre les traits. Merci !


    • saucyindexer says:

      Merci, Maurice. Votre commentaire m’a rappelé: j’ai oublié d’inclure la plaque 5 de Roubo!


  3. Bob Easton says:

    THANKS Suzanne!
    These collections of similar things are always delightful. I always appreciate the effort it takes to collect and present them. Thanks!

    …and in addition to the common theme across cultures and centuries, we also get the bonuses of seeing interesting hairdos, headgear, and clothing for wear in one’s workshop.


  4. Roher H. says:

    Thanks for an informative, great presentation!


  5. johncashman73 says:

    Wow. You put a lot of effort into these. I appreciate it, very much.

    Seeing the image of young Jesus working with Joseph really brought back memories. Working with my dad at about the same age, I used to get called “Jesus H. Christ!” all the time.

    Liked by 1 person

    • saucyindexer says:

      So, you got a little teary-eyed? As soon as I read “really brought back memories” I knew there would be a Cashman twist.


      • johncashman73 says:

        I’d like to know why that dude in the 1440 Catherine of Cleves image is dressed like an alligator.


        • saucyindexer says:

          You noticed that, too. My first thought was a giant cabbage leaf but now I’m leaning towards alligator.


  6. Erik Hoover says:



  7. tsstahl says:

    I appreciate your effort. Nice work. Add one vote for carpentry fashion show. 🙂 The French woodworkers appear to be auditioning for roles in a cuckoo clock.


  8. Pascal Teste says:

    Thank you for the interesting post. The Chinese shipwright’s mondou is pretty wild!


  9. joefromoklahoma says:

    My exact same face the first time I helped snap a line! I still think of it as some kind of magic that only we know. Thanks, Joe


  10. Jerry Strojny says:

    Absolutely fascinating. So cool to see it throughout history.


  11. mjstauss says:

    Great post! My path to woodworking started with carpentry while working as a roofer on slate and copper roofs. Snapping a clean line was important business, and a bit more fun with a 100′ roofing line. It’s one of those things that’s hard to explain why it’s so satisfying.


  12. Mike says:

    Excellent article, well written, informative, and fun. Thank you, Suzanne! (Coppyedit note: three occurrences of “sumitsubo” as “sumistubo.”)


    • saucyindexer says:

      Thanks! I knew I reversed the letters a few times as the clock went well past midnight. I will get them corrected.


  13. Mike Siemsen says:

    Chalk also comes in red, orange and black as well as the blue. Woo Hoo!!
    Now a lot of it is done with a laser.


  14. Meadowlane Woodworks says:

    Excellent read! I love learning about historical methods and tools. Technology is great, but I think something more important is lost than gained when you add electricity.


  15. Fred Beck says:

    This was wonderful. Was it like where’s waldo seeking out all these chalk line images?


    • saucyindexer says:

      It can be like that if the image is low resolution. Otherwise, I usually home in on the line snap right away.


  16. Quercus Robur says:

    Fantastic! I love those “nothing new under the sun” posts, it’s like my favorite musical structure (theme and variations) transformed into a visual form.


  17. Will Truax says:

    How far back does this line wind?

    I don’t think it a stretch to suggest it is our very beginnings! How important is this simple tool?

    I wondered after that here >


  18. Eric Uglem says:

    Wow! what an incredible article, you’ve certainly done your research, I’ve never even heard of these sumitsubo ink lines. I love the fish shaped ones as well. Thankyou !


  19. Dear ​​Suzanne,
    When this one popped up on my queue to be read I set it aside for a time to give it the attention (and enjoyment) it deserves. I could tell at a glance this was a “good one” and a topic special to both our hearts!!!

    For me…”lining methods”…as I was taught there concept, ​(​Family traditions, Japanese/Korean and Older Amish) in all the many forms, has been the soul of my crafts over the decades. Without them, I could not work day to day in what I do. Whether creating a garment, layout of a scarf in stone or fashioning the intricacies of a timber frame, these methods are crucial, as you well know. I have loved and been fascinated by there modalities and history. So, to find you post (and interest) is a treasure to be sure…Many thanks​ for writing this​…​​

    ​Your references to the origins in the Middle East (Egypt and Biblical reference) is in line with the countless documents I have read and the theories I hold to about the spread of “lining modalities” stemming from Africa-Middle East up into Asia and Europe. Did these systems coevolve or spread is a topic of academic debate for sure, with mix of both most likely being the reality of the acient historical origins. It seems in Europe they evolved mostly into “scribe rule” and “lofting” methods while in the Middle East and Asia (for the most part) into “Soul Line” systems. Overlap of course clearly exists, especially when we examine further the craft of the Shipwrights both in the Middle East, Europe and Asia.

    ​Just following 鲁班​ ​(Lu Ban) ​and the 魯班經 Lǔbān jīng – Handbook on architecture from the Ming period​ ​​​references much of this, as well as, other Chinese timber framing and woodworking applications as they spread again in the latter origins (often with temple building architecture) from India through China and on into the ​대조선국​ ​(Josen – ​Korean peninsula​)​ deepens the understanding of this history and how it evolved and migrated.

    I​ must admit, you lost me a bit with your reference of the “ink pot” from Chine as a “modou”, yet I do understand that translation to English is often tricky. If you have more orgin history to this reference (as you understand it,) I would love to read more! In the meantime, I believe the more common terms from Asia for “ink pots” (or “ink lines”) are as follows: ​China – ​墨壶( Mò hú) ​Korean – 먹통 (Meogtong)​ and from Japan – 墨壷 (Sumitsubo​.​)​​​​ Your reference to ​김준근​ (​Kim Jun-geun​)​ is excellent, and if you research him in the native language you will find even more works illustrated.

    I fully admit being more versed in the more acient Middle Eastern and Asian system of line layout and your post has revitalized my desire to look more deeply in the Europe modalities further than I have. French and German lofting and scribing methods I only have a parochial application understanding off, just well enough to pull off a Cruck Frame in the orgin form if I had to. The “square ink box” is a memory from my youth employed by the Old Order Amish Barnwrights I was fortunate to study under for a time. They reference this often in “Amish Dutch” but I’m not that good with the languages to even attempt repeating it in written form. I know in English it would be called a “grease line” or “line box.” In one version it was just a course line in the box, while the other was a box and within was an axle and finer line wrapped around it very reminiscent (?) from a more crude or rustic version of the “ink pots” of Asia but larger. I’ve meant for some time to refashion one of these as I remember it.

    ​Any further more you learn of these methods and history ​​Suzanne would be of keen interest to me and I’m sure others. Many Thanks for this post!!!



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