If you shoot a bamboo bow, sooner or later someone at the dojo will tell you to switch to a hemp string — asazuru (麻弦). Then you open a Japanese shop page and find the sizes written as “1.6匁” or “1.8匁” instead of the numbers you know from synthetic strings.
This page explains how hemp strings are sized, how Japanese kyudo shops match a size to your bow’s draw weight, why a thicker string is suggested in dry weather, and how long a hemp string can be expected to last. For the overview of synthetic versus hemp strings, start with Choosing a Kyudo Bowstring.
The short version
- Hemp strings are sized in monme (匁), an old Japanese unit of weight. Synthetic strings are sized in gō (号). The two scales are separate: a bigger number means a heavier, thicker string in each, but you cannot convert one into the other.
- Pick the monme from your bow’s draw weight in kilograms. Shop listings give a guide, and the guide can differ slightly between brands at the same monme.
- Hemp is weak against dryness. One shop suggests a thicker string than usual in dry periods.
- The string’s length class must match the bow (sansun-tsumari, namisun, nisun-nobi, yonsun-nobi).
- One shop’s guideline is around 300 shots in normal use, shorter than a synthetic string. Keep a spare ready.
A string made for bamboo bows
The All Japan Kyudo Equipment Association describes a hemp string as one “made by twisting hemp together using a traditional method”, and says it is “used mainly on bamboo bows” (All Japan Kyudo Equipment Association: choosing kyudo equipment, Japanese). Suizan Kyugu-ten, a kyudo shop, says the same, and describes hemp’s character as stretching less than a synthetic string and giving a clean tsurune — the sound the string makes at the release (Suizan: how to choose a bowstring, Japanese).
Why does a bamboo bow want hemp? Suizan’s hemp string page gives one reason directly: bamboo bows can be damaged by the strong shock of a synthetic string (Suizan: hemp string “Fuji”).
There is a second idea behind it. The glass-bow maker Miyata, in a safety notice published by Sambu Kyugu-ten, describes the string as a safety device that protects the bow when a bad shot happens, and recommends either hemp or a synthetic string that breaks properly in that situation (Miyata notice on Sambu Kyugu-ten, PDF, Japanese). In other words, a string is also a part that protects the bow by breaking.
If you shoot a glass or carbon bow and are wondering about hemp, ask the bow’s maker or your instructor first.
Size: choose by monme
The rule is simple: the stronger the bow, the heavier and thicker the string. Once you know your bow’s draw weight (kyūryoku, 弓力) in kilograms, the monme is almost decided. If you are not sure of your bow’s draw weight, ask your instructor or the shop that supplied the bow.
Monme and draw weight: what the shop pages say
These are the guides on Suizan Kyugu-ten’s product pages for two hemp strings, “Fuji” (富士) and “Katsura Bessaku” (桂 別作), as checked on 5 November 2026. Each figure is the upper end of draw weight for that size.
| Monme | Suizan “Fuji” | Suizan “Katsura Bessaku” |
|---|---|---|
| 1.4 | up to 12 kg | — |
| 1.5 | up to 13 kg | up to 12 kg |
| 1.6 | up to 14 kg | up to 14 kg |
| 1.7 | up to 16 kg | up to 16 kg |
| 1.8 | up to 18 kg | up to 18 kg |
| 1.9 | up to 19 kg | up to 19 kg |
| 2.0 | up to 20 kg | up to 20 kg |
Sources: Suizan: Fuji / Suizan: Katsura Bessaku.
Look at the 1.5 monme row: 12 kg for one brand, 13 kg for the other. Sambu Kyugu-ten’s listing for Fuji gives 1.5 monme as “13 kg or less” (Sambu: Fuji). So the same number does not mean exactly the same string everywhere — read the product page for the brand you are buying.
The Fuji page also notes that from January 2026 the quality of the raw hemp was improved and the amount of hemp used changed; for 2.0 monme, the page lists 12 g of hemp for the old version and 10 g for the new one. If you are moving to a different thickness or buying several at once, it is worth reading the current description rather than relying on what you bought last time.
Dry seasons: a thicker string
Sambu Kyugu-ten’s listing for Fuji gives this warning: hemp is weak against dryness, and in dry periods a string thicker than usual is recommended. The same listing adds a preparation step for dry weather: before use, dampen the whole string, for example with steam, then work kusune (the bowstring resin) well into it with a magusune (a leather pad used to rub the resin in) (Sambu: Fuji). Suizan’s hemp string pages say that because these are boiled strings, in winter they should always be treated with asa-gusune (resin for hemp strings) before use.
Japanese winters are dry, and so are many indoor ranges and climates abroad. If you are starting a new hemp string in a dry season, ask your instructor or the shop whether to go one step thicker than the table above.
Length: match your bow’s size class
Suizan’s instruction is to choose a string of the same size as your bow’s length class — sansun-tsumari (三寸詰), namisun (並寸), nisun-nobi (二寸伸) or yonsun-nobi (四寸伸). A namisun bow takes a namisun string. Hemp strings are listed by these size classes.
How long a hemp string lasts
Suizan’s hemp string page says that in normal use a hemp string lasts around 300 shots. For synthetic strings, the same shop gives about 600–700 shots as the usual replacement guideline. Hemp, in other words, wears out sooner. More on replacement timing in Kyudo Bowstrings: Replace at 600 Shots.
Sambu Kyugu-ten notes that because hemp is a natural material, strength differs from one string to another. Keep one spare string ready at all times — already looped and treated, not still in its packet.
Loops: remake them as little as possible
The tsuruwa (弦輪) is the loop at each end of the string that hooks over the bow tips. The All Nippon Kyudo Federation warns that “if you correct the loop repeatedly, the string becomes more likely to break” (All Nippon Kyudo Federation: about equipment, Japanese). Suizan’s hemp string page says that it is best to be able to make a loop within about two attempts.
Because each hemp string has a shorter life, you will be tying loops more often than with synthetic strings. For your first few strings, have your instructor or a kyudo shop watch you tie the loop — it saves strings.
Prices (official shop pages, checked 5 November 2026, including Japanese consumption tax)
| String and pack | Shop | Price (as of November 2026) |
|---|---|---|
| Fuji, namisun, pack of 2 | Suizan Kyugu-ten | 3,410 yen |
| Fuji, namisun, pack of 2 | Sambu Kyugu-ten | 4,290 yen (1.5–2.2 monme) / 4,660 yen (2.3 monme) / 5,030 yen (2.4 monme) |
| Katsura Bessaku, namisun, single | Suizan Kyugu-ten | 2,640 yen |
Sources: Suizan: Fuji / Sambu: Fuji / Suizan: Katsura Bessaku. Prices change; check each shop’s page before ordering.
FAQ
How does a synthetic string’s gō correspond to a hemp string’s monme? There is no simple conversion. Choose hemp by your draw weight in kilograms, using the monme guide on the product page of the brand you are buying.
What changes when I switch to hemp? The string stretches less and gives a clean tsurune. It lasts roughly 300 shots, needs more attention to dryness and kusune, and may need to be a size thicker in dry weather.
When should I start using hemp? Both Suizan and the Equipment Association describe hemp as a string mainly for bamboo bows. When you move to a bamboo bow depends on your dojo and teacher, so ask your instructor or a kyudo shop first.
Summary
- Hemp strings are sized in monme; choose by draw weight in kg, and read the brand’s own guide.
- Dry season → consider one size thicker; dampen and work in kusune before use.
- Length class must match the bow.
- Expect around 300 shots and keep a ready spare.
- Tie loops carefully and rarely — repeated corrections make the string more likely to break.
Descriptions, size guides and prices on this page come from the official pages of the All Japan Kyudo Equipment Association, the All Nippon Kyudo Federation, Suizan Kyugu-ten and Sambu Kyugu-ten, checked on 5 November 2026, and may change. Before buying, check the current shop page and ask your instructor or a kyudo equipment shop.