Kyudo Notebook: Tsuru

I just had to tie a bunch of bowstrings so I just want to make some notes to myself for future reference:

  • To determine the length, put the lower loop over the urahazu and pull the string taut. The correct place for the bottom of the knot on the upper loop is apparently already marked by a line across the kilogram label on the bows from Terauchi Kyuguten (no web site). Mark that with a pencil.
  • Tie the loop so that, before you make the knot, it is snug (but not too tight) around your thumb at the base of the thumbnail. Obviously this will vary with thumb size but that’s what seems to work for me.
  • Using the two-loop method, be sure to tie the knot so that the pencil mark is just barely visible.
  • Sometimes in cold weather it helps to warm the upper (red) part of the string over a heater, or just with friction, so that the kusune melts, but in summer you get the opposite problem and the whole string is sticky.
  • Tie it and try it. Adjust if necessary. Since I’m making strings for 4-sun nobi bows, the distance from the grip to the string should be 16cm. If you make that a little higher the string should be just right when it stretches out a little after the first couple of shots. But no more than a few mm or the bow will be unhappy.
  • The loop will seem small and you may have to push it down onto the bow at first.

For the nakajikake:

  • You need about a 20cm length of asa (hemp), flat, and maybe 1.5mm wide. Unfortunately the stuff that comes with my favourite strings is cut 14cm long, which I guess must be the standard, but for some reason that doesn’t work well for me.
  • Mark the spot opposite the top of the grip by using an arrow: Holding the bow vertically, put the tip of the arrow down at the motohazu of the bow, then tilt it until it touches the top of the grip. Mark that spot on the arrow (or just keep your fingers there), then tilt the arrow back to vertical to line up with the string. Use a pencil to mark the place (call this point B) where the mark on the arrow touches the string. Because of the geometry, point B on the string to be slightly higher than the top of the grip, which is what you want.
  • Now mark a spot on the string 2cm above that (call this mark A), and 1cm below that (mark C). This 3cm area (A-B-C) is the critical area where the hazu will contact the string.
  • Apply the glue from mark A down to a place 9cm below. Call that mark D.
  • With the bow facing away from you (string facing toward you) hold the asa behind the string so that 6cm is to the right of mark A and the rest to the left. Wind that 6cm clockwise (as seen from above) down from A, over point B, to point C.
  • You may want to refresh the glue from A-B-C a bit, and then wind the left-hand 14cm of the asa anti-clockwise (as seen from above) around the string all the way down to point D. Note that because A-B-C gets two wrappings it will be twice as thick as the area from C to D, which where the glove will contact the string.
  • Try to keep the asa flat, rather than letting it twist. If it twists, it will become thinner (like thread) and you may need more (is that why I need 20cm rather than 14?)
  • Then finish the nakajikake with the dohou, the two blocks of wood, sliding the one to the right forward while pulling the one on the left back, thus giving the the nakajikake an anticlockwise twist (matching the way the fibres in the string are twisted).
  • Let it sit for a while until the glue dries, then wind the new string into a tsurumaki.

A useful hint I got the other day from a veteran is to use one of the larger, wider tsurumaki and keep three strings in it. Each string should be used a few times to “season” it, then you can wind them on. The trick is that the first one you wind onto the tsurumaki should a synthetic one. The remaining two should be asa. The idea is that if you are at a taikai, you start with the top (hemp) string. If that breaks, you have a second hemp string that is ready to go (have fun sitting in kiza while they deal with that). And if that breaks, you still have an unbreakable synthetic string as a final backup.

She says that the tsurune is noticeably different with asa versus synthetics, so it’s best to use the natural materials, but if you’re having one of “those” days, the final synthetic string could save you.

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10 Responses to Kyudo Notebook: Tsuru

  1. J-Boon says:

    I happen to chance on your blog while browsing the internet. I hope I’m not bothering you by writing in regarding questions about the Japanese bow.

    I’m not a practitioner of Kyudo, although I do traditional style archery using an asymmetrical ‘hun style bow’ with a thumb draw. I’m interested in learning about the facts and equipment about other forms of traditional style archery of the world.

    1. In Kyudo, is there a reason why the center serving (nakajikake) is done with hemp and rubbed with glue, instead of using a modern center serving jig? Is this for traditional reason, or is there a technical reason why a modern center serving jig not used when making the center serving?

    2. I saw your comment about “hints on kyudo strings’ and you mention about “unbreakable synthetic string”. I have read that in kyudo, strings do break. Is the breaking of strings in kyudo mostly associated with hemp strings and not so much in synthetics? How often do synthetic strings break in kyudo (or do they never?) What material is used for these synthetic strings?

    Thanks for your response.

    • karamatsu says:

      Hello! I’m sorry about the delay. I’m just starting to figure out how this software works! About the strings:

      (1) I think there are probably several reasons. One is tradition, but another may have to do with the way different materials work together. Advanced people tend to use all natural materials, and I was told a while back that to get the best tsurune, all of the materials have to match. So that maybe part of it. That said, I’m not familiar with the modern serving (I didn’t even know it was called that), but I imagine that teachers who practice both kyudo and archery have tried just about everything over the years. What is the modern serving like?

      (2) I think what it comes down to is that the natural materials are more sensitive, and so need to be handled more carefully. This is not to say that they are more fragile, but that they have to be handled correctly, whereas something like fibreglass bows and synthetic strings can survive more rough handling. Perhaps you could say that the natural bows/strings/arrows are much more “finely tuned,” or “precision instruments,” and like anything that is finely tuned, they’re easier to break if you don’t treat them well.

      So with strings, I’ve been told that the best ones (like the ones called katsura) can break the very first time you use them… unless your form is correct. At the same time, in the hands of someone who is very good, the same string might last months or even (I’ve heard) years. Advanced people tend to recognize that certain equipment (bows by a certain bow-maker, strings by a certain string-maker, arrows by a certain arrow-maker) matches the way they shoot, while others less so, and they naturally gravitate toward what works best for their shooting style. It takes time, money (!), experience, and experimentation, but I imagine that once you find what works for you, the natural hemp strings can last a long time.

      The synthetic ones seem to be made of stuff like kevlar or aramid fibres. I don’t know if they are truly unbreakable, to be honest. I’ve seen some students break strings, so I guess it’s possible, but none of mine have ever broken. Their toughness can be a problem, though, if the string is too loose and/or used by someone who doesn’t have a reliable tenouchi because what can happen is that the bow kind of turns inside-out. With a hemp string, you can just cut it, but the kevlar ones can’t be cut (or at least not easily). You can bend a fiberglass bow, take the string off, and it will be OK, but a bamboo bow could be ruined. That may be one practical reason why people using bamboo bows also tend to use natural strings. But what they talk about most is the sound. They say it is easy to tell the difference in sound between a hemp string and one of the synthetics.

  2. J-Boon says:

    Thank you for taking the time to read and reply to my message, I greatly appreciate your kindness. For a modern center serving, a device known commonly as a serving jig is used to re-enforce the nocking area. The device and how a string serving jig (nakajikake) looks like can be seen in a Youtube link I found ( titled “3Rivers Archery Crafting Traditional Strings: Serving String “. I’m not sure if this device can be used to install the hemp Nakajikake used in Japanese strings.

    Are Japanese bowstrings waxed regularly, or left as it is? I was just thinking if so, won’t a ‘waxed’ string be ‘crack-ly” when wound around a Tsurumaki?

    I strongly agree with you that natural materials are more sensitive. My interest is mainly with the Asiatic horn and animal sinew composite bow, and they too, appear to be much more ‘delicate’ (i.e temperature/humidity) than modern fiberglass composites.

    You mentioned that the yumi can turn inside out (de-flex), is this a common occurrence of the yumi? or is this mainly attributed to an improper technique?

  3. karamatsu says:

    Good questions! The strings usually come with a kind of natural glue called kusune binding the fibers. Although I have seen people rub new kusune on them, the coating is a bit thick and most people simply rub the string with a hemp pad (waraji) before and after practising. The friction of rubbing melts the kusune and helps to redistribute it evenly. It probably also reduces some tension in the string itself that occurs when the string is twisted to take up slack. I don’t notice any crackling when winding the string around a tsurumaki, maybe because the kusune flexes more than wax (?). It can be a little sticky in summer. But in winter it can happen that the layer of kusune around the string will kind of crack, so you see little white bends in the kusune when you unwind it later. Rubbing the string will make those disappear, though.

    You’re quite right about the temperature and humidity. The teachers check both of these at each practice session and seem to be aware of how their bows will respond to the differences, but I’m not at that level! It’s kind of a problem for us here, really, because the bows are often made in southern Japan, where humidity is higher for most of the year. But here we have very low (absolute) humidity for 5-6 months of winter, which is hard on the natural materials.

    I think the de-flexing occurs mostly due to improper technique or to some aspect of the bow or string, like when the string is too loose. I suppose it’s all a question of where the energy of the release propels the limbs of the bow. If the energy is transferred into the yugaeri, perhaps there is little danger of de-flexing, but people starting out tend to hold the bow too tightly, so the yugaeri action cannot take place. If you combine that with a loose string, it’s pretty easy to have the bow de-flex, or come close to it. Eventually you can hear/feel it when there’s a danger, and tighten the string before something bad happens.

    Another thing people do sometimes to avoid the problem is to string the bow in reverse, which is hard to explain in words… the upper loop has the knot tied so that the free end winds around the loop to the right and the lower loop is the opposite way. To counteract the de-flexing action a bit, you can string it so that the free end of the upper loop is wound around the left side of the loop. It seems to help, especially if a bow has de-flexed before and has become a little warped. Even the fibreglass ones will start to twist a bit.

    Thanks for the link! I will look at that when I get home. It must be difficult to get the materials to make horn and sinew bows!

  4. Maciej says:

    Hello Karamatsu;

    I’ve been quietly following your notebook for some time 😉
    It is a great resource for me (as I don’t have access to Kyudo clubs / coaches in Ireland).
    Thank you for sharing your experience!

    I have a question on the nakajikake:

    the main purpose is to hold the arrow nock (3cm), but what is the importance of the remaining 10cm below? I use the synthetic string (or should I say, “will be” using as I have my first shooting day this evening!) and I’m worried that it may damage the hard thumb on the glove?
    Synthetic material is probably tougher than the glove horn so it may shave a bit of it with every shot?

    Also if the nakajikake is too thick for the arrow nock (but is properly done) is it better to make a new nakajikake / crush it thinner with pliers, or to open up the nock on the arrow?

    Kind regards,


    • karamatsu says:

      Probably the reason for the length below the nocking point is, as you suggest, to protect the tsuru-makura and provide a bigger surface to engage it, but now that you mention it, I’ve never heard exactly why, so it’s my best guess! Also it probably helps to protect the string from the friction and pressure during the draw, though that’s probably less an issue with synthetic strings than with hemp. It’s a good question!
      But the tsuru-makura is pretty tough and, and is usually protected with a layer of kusune (on a new kake it looks like a layer of hard wax). That layer will be slowly abraded away, and if it gets to the point where you see the deerskin, it’s best to apply more kusune. Conveniently, I just wrote about how to do that a few posts ago (look for Kyudo Notebook: Maintenance), but in my case, anyway, it usually takes about six months (maybe 1,800 arrows) to get to that point.
      When I happen to make the nakajikake too thick, what I usually do is press down on it from both sides with douhou, the wood blocks that you use to finish the nakajikake. I avoid pliers because the serrated surface could do more harm than good, though I’ve seen jeweler’s pliers, with a smooth surface, that might work. Another thing I do when it’s not too, too bad is just nock an arrow and then sort of lift and lower it a few times in the process of removing it. That usually compresses it down well enough. But do what you have to… In the worst case I’d probably re-do the nakajikake rather than widening the gap in the nock, because once you do that you can never go back, plus you’d have to widen the gap for all of your arrows, which is also kind of error-prone. Getting it right could take some time!

      It’s impressive that you’re doing so much without any teachers or even a place to practice. If anyone comes to the Nagoya seminar from Ireland I’ll let you know. Otherwise if you have a few days sometime, there are excellent teachers in England. Liam O’Brien, who translated the Kyudo Kyohon, teaches there, for example, and a good teacher at the beginning makes a big difference (otherwise it’s easy to get into bad habits). But feel free to ask anything. I’m happy to help and if I don’t know the answer about something, I’ll ask someone who does!

  5. Maciej says:

    Hello Karamatsu;

    thank you for your reply.
    After few broken strings it seems that the lower portion of nakajikake is there to protect the string. During the draw the string bends round the thumb. Because the thumb is hard, its edge may (and will) gradually damage the string with each release. So fibre after fibre the string will get thinner until it eventually breaks. I’ve observed that happening on my strings, they all broke in the same place and that was around the nakajikake area. Because the thumb folds the string in two places above and below the thumb, whichever place is less protected will be damaged more.
    I’ve been making the nakajikake too short and the string was exposed to the thumb.
    The thumb itself does not seem to wear.

    Thanks for the tip on using douhou, it does the trick.

    Training on my own has some benefits, I can’t rely on the teacher to teach me, so I end up actively learning and resolving the problems myself. I record my shooting with high speed camera and then analyse and compare them with books and youtube videos. I may be getting a bit fuller understanding this way as I also learn what happens when you don’t follow the prescribed path ;). Unfortunately, a lot of lessons tend to manifest themselves through pain – but at least that way they are memorized forever :).
    I will try to go for training session to a club in UK after the summer, hopefully to the club where Mr. Liam O’Brien teaches. It really surprises me how many different things I’ve learned so far in something seemingly so simple as shooting an arrow with the bow – and at the same time there is so much more to learn…

    • karamatsu says:

      Oh, it’s an endless process, apparently! Such a simple thing and yet… not! You might consider coming to the Nagoya seminar next April if time and budget allow. It’s very good, but naturally, a long, long trip. Later on these early videos will be something to look back on, too!

  6. chris colman says:

    Something I learned this year – when using natural hemp tsuru, Assa, don’t use PVA type glue to make the nakajikake, use Nori glue- this is a water/starch glue like wallpaper paste. The nakajikake made with PVA is too hard for the natural tsuru and they tend to break at the base of it.
    I haven’t found out how long the tsuru will last with this method yet, Assa strings were generally lasting about two weeks when I was shooting nearly every day 30 to 40 arrows using PVA glue

  7. karamatsu says:

    I’d never heard that but it would certainly be nice to use entirely natural materials, even down to the glue. I did try using kusune once, on the advice of one of the sempai in my dojo, but it was a bit difficult to use. I think I need to get one of those lumps of it that you sometimes see at kyudo shops. I find that I probably do get about 300/string on average. More during the summer, less in winter when the humidity is so much lower. Some people at our dojo switch to synthetics during the winter for that reason: it’s too expensive to break one string after another!

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