The string (tsuru, 弦) is the piece of kyudo equipment you will buy most often. Before your first one, it helps to know that there are two families of string, that they are sized in two different units, and that a string has to match both the strength and the length of your bow.
The short answer
- There are two kinds: synthetic-fibre strings (合成弦, gōsei-zuru) and hemp strings (麻弦, asa-zuru). Both the All Japan Kyudo Equipment Association and Suizan Kyugu, a kyudo shop, divide them this way.
- Synthetic strings are made from fibres such as Kevlar and aramid. The Association describes them as inexpensive and durable.
- Hemp strings are made the traditional way, by twisting hemp, and the Association says they are used mainly on bamboo bows. Suizan says they stretch less than synthetic strings and give a clean tsurune (the sound of the string at release).
- Thickness is numbered differently: synthetic strings in gō (号), hemp strings in monme (匁). In general, the bigger the number, the heavier and thicker the string.
- The stronger the bow, the thicker and heavier the string (the Association).
- The string must match the bow’s length. Suizan’s example: a string for a namisun bow does not fit a nisun-nobi bow.
Synthetic or hemp
| Synthetic-fibre string (合成弦) | Hemp string (麻弦) | |
|---|---|---|
| Made from | Fibres such as Kevlar and aramid | Hemp, twisted by a traditional method |
| How the sources describe it | Inexpensive and durable (Association) | Stretches less, clean tsurune (Suizan) |
| Usually used on | — | Mainly bamboo bows (Association) |
| Thickness unit | gō (号) | monme (匁) |
Which one to use is a question for your teacher and dojo. The Association also notes that strings differ not only by material but by how they are made — the twist, the bonding, and the material of the loops — and that this changes durability and sound. It suggests trying different strings to find the one that suits you.
Using a synthetic string on a bamboo bow
Suizan Kyugu adds a caution: if you use a synthetic string on a bamboo bow, use a bamboo bow built to take synthetic strings. If you shoot a bamboo bow, ask the maker or a kyudo shop whether yours is one of them before you change string type. How bamboo and synthetic bows differ is covered in Bamboo or synthetic yumi?.
How thickness is numbered: gō and monme
Do not read a hemp string’s number on the same scale as a synthetic one. The Association is explicit: synthetic strings are sized in gō and hemp strings in monme. Within each system, a larger number generally means a heavier, thicker string.
The thickness is chosen to suit the bow. The Association’s rule is simple: the stronger the bow, the thicker and heavier the string you use. So the first thing to know is your bow’s draw weight; see Kyudo bow strength. Then ask your teacher or a kyudo shop which gō (or monme) matches that bow.
Matching the string to the bow’s length
Strings come in lengths that follow the bow: the Association lists sansun-tsumari, namisun, nobisun, yonsun-nobi and so on. Suizan’s warning is the practical one: a string made for a namisun bow will not fit a nisun-nobi bow, so check your own bow’s length before you order. If you are not sure which length your bow is, ask your teacher or the shop before ordering.
When the string is new
Synthetic strings stretch easily when new. Suizan recommends tying the loop (tsuruwa) a little short of the right length at first. The loop at the top of the bow (urahazu) is commonly red and the one at the bottom (motohazu) white, according to Suizan.
What to tell the shop
Whether you order from a kyudo shop in Japan or a retailer near you, have these ready:
- String type — synthetic or hemp (and, for a bamboo bow, whether it is built for synthetic strings).
- Bow length — namisun, nobisun, sansun-tsumari, etc.
- Bow strength — so the shop can suggest the gō or monme.
- How many — you will want spares. Suizan gives 600 to 700 shots as the usual point to replace a synthetic string; see When to replace a kyudo bowstring.
Frequently asked questions
Is a higher gō always better?
No. The number is a size, not a grade. The right size depends on your bow’s strength.
Can I compare a gō number with a monme number?
No. They are different units for different materials.
Should a beginner use hemp?
Follow your dojo and teacher. The Association says hemp strings are mainly used on bamboo bows.
Summary
- Two kinds: synthetic-fibre (Kevlar, aramid) and hemp.
- Synthetic is sized in gō, hemp in monme; bigger number, thicker string.
- Stronger bow, thicker string. Match the length to your bow.
- On a bamboo bow, use synthetic strings only if the bow is built for them.
Sources (checked 19 October 2026): All Japan Kyudo Equipment Association — Choosing kyudo equipment (弓道具の選び方) / Suizan Kyugu — Choosing a bowstring (弦の選び方)