# Water scarer

> A bamboo tube that fills, tips and knocks on a stone

- Date: 1305
- Era: Middle Ages
- Domain: [Agriculture & Livestock](https://lastcodex.org/en/domains/agriculture/)
- Rebuild stage: II (Settlement)
- Difficulty: 2/5
- URL: https://lastcodex.org/en/inventions/water-scarecrow/

A water scarer, called sōzu or shishi-odoshi in Japan, is a bamboo tube on a pivot that fills with running water, tips forward to empty, then falls back onto a stone with a sharp knock. It repeats this for as long as the water flows, and the noise was meant to drive deer, boar and birds away from crops. The oldest known mention is a Japanese poem in an anthology of 1305, about the sound of a sōzu growing rare as its water slackens.

![Water scarer · A bamboo tube that fills, tips and knocks on a stone](https://lastcodex.org/_astro/plate.2QitLr9i_2mmd7g.webp)

## Legend

1. Bamboo pipe bringing the water
2. Open mouth of the tube, cut on a slant
3. Node closing the water chamber
4. Pivot pin between two posts
5. Striking stone under the closed end

## What it is

A water scarer is a noise-maker driven by a stream. A length of bamboo is cut so that one end is an open scoop and the other is closed, and it is hung on a pin between two short posts so that it can rock. A thin bamboo pipe brings water to the scoop. At intervals set by the flow, the tube tips, pours out its water and swings back to strike a stone placed under its closed end.

In Japan the device is called sōzu or shishi-odoshi, "deer scarer". Japanese dictionaries describe it as set beside valley streams and rivers to drive off the animals that damage fields, and later built into gardens for its sound. A larger version with a pestle in place of the knocking end pounded grain. Today it is best known as a feature of Japanese gardens, where the regular knock breaks the quiet.

## How it works

![Three small views of the same bamboo tube on its pivot beside a stone-lined pool: filling under the spout with its closed end on the stone, tipped forward and pouring out its water, and fallen back with its closed end striking the stone](https://lastcodex.org/_astro/v1.tIv7uAXF_Z1NHRDJ.webp)
_Filling, tipping and striking: the tube rocks through the same three positions for as long as the water runs._

The tube is a lever balanced on its pin. Inside, a node of the bamboo closes off the front part, which forms the water chamber, and the pin passes through the tube just behind that node. With the chamber empty, the long rear part outweighs the front. The closed end rests on the stone and the open mouth points upward under the pipe.

As water runs in, the weight in front of the pin grows. When its turning effect becomes larger than that of the rear part, the tube rocks forward, the mouth drops and the water pours out. The slanted cut lets it empty quickly, so the tube does not stop half way in balance. Once the chamber is empty, the rear part is the heavier side again. It falls back and the closed end strikes the stone. Then the filling starts again, with no one to tend it.

The interval between knocks depends on how fast the water arrives and how much the chamber holds. A stronger flow fills it sooner and the knocks come faster. Like the [scarecrow](/en/inventions/scarecrow/), the device relies on surprise: a sudden sharp sound in a quiet valley startles a deer or a boar, but animals that hear the same harmless knock again and again can learn to ignore it.

## How to do it

![A bamboo tube on a workbench beside the same tube split lengthwise to show the slanted mouth, the inner node closing the chamber, the pin hole just behind it and the node sealing the far end, with a small wooden pin and shavings beside them](https://lastcodex.org/_astro/v2.B9Q0J8vS_239Ylv.webp)
_The inner node closes the water chamber; the pin hole is drilled just behind it._

A small garden model needs a length of dry bamboo with two nodes, a hardwood pin, two wooden stakes and a flat stone. Saw the tube just behind one node so that this end stays sealed. Leave a second node inside, and at the other end cut across at a steep slant, so that the open part in front of the inner node becomes a scoop. Clamp the bamboo before sawing and file off the sharp edges.

Lay the empty tube on a finger to find where it balances; this point must lie behind the inner node. Drill the pin hole straight through the tube a little in front of the balance point, toward the mouth, so that the empty tube comes to rest on its closed end. Drive the two stakes into the ground on either side, drill them at the same height, and pass the pin through stakes and tube. The tube must turn freely on the pin. Set the flat stone where the closed end will strike it.

Bring water to the mouth through a thin bamboo pipe, from a stream, a rain barrel or a small fountain pump that sends the water from a basin back to the pipe. If the full tube does not tip, the pin is too far forward; if the empty tube does not fall back, it is too far back. Move it a little at a time until the tube tips, empties and strikes cleanly.

Safety: saws and split bamboo cut, so wear gloves and clamp the work. Even shallow water can drown a small child; keep a basin covered with a grid or supervise children near it. A pump must be made for outdoor use and plugged into a socket protected by a residual-current device, with its cable kept out of the water. Keep the water moving or empty the basin often so that mosquitoes do not breed in it.

## History and evolution

The oldest known mention is in poetry. The Nihon Kokugo Daijiten, the large historical dictionary of Japanese, cites a poem from the Zoku Mon'yō wakashū, an anthology compiled in 1305, in which the poet wonders whether the water let in from upstream has slackened, since the sound of the sōzu has become rare. The origin of the name is uncertain: dictionaries derive it either from sōzu, a rank of Buddhist priest, or from sohodo, an old word for a scarecrow. In haikai poetry the sōzu became a season word for autumn.

![A water-powered grain pounder under an open thatched shed: a long wooden beam on a pivot between two posts, a hollowed trough at one end under a water pipe, and a wooden pestle at the other end above a mortar holding grain](https://lastcodex.org/_astro/v3.ObgQJyn6_ZCGngx.webp)
_A grain pounder uses the same rocking beam: the water lifts the pestle, and the pestle drops into the mortar._

The same rocking principle was put to work. In the version with a pestle, the trough end fills and sinks, lifting the pestle; when the water spills out, the pestle drops into a mortar and husks or pounds the grain. Such pounders were shared by a household or by neighbours where water was scarce. The Shikoku Mura open-air museum in Takamatsu shows a reconstruction of one from the former village of Ichiu, in Tokushima Prefecture. In the potters' village of Onta, near Hita in Ōita Prefecture, pounders of this kind driven by the river still crush the clay.

In gardens the knock became a sound to enjoy. A haikai collection of 1663 explains that the sōzu is set by the water and uses the force of the water to make a noise that scares deer. One still sounds in the garden of Shisen-dō, the hermitage in northern Kyoto that the scholar and garden designer Ishikawa Jōzan completed in 1641. Gunter Nitschke, writing on Japanese gardens, describes the device as a bamboo pole balanced on an axle that fills, tips and swings back against a rock, and notes the popular account that farmers first built it against deer and wild boar.

## Key facts

- Oldest known mention: A poem in the Zoku Mon'yō wakashū, a Japanese anthology of 1305
- Japanese names: Sōzu (添水); shishi-odoshi, "deer scarer"
- Power: Running water alone; it knocks for as long as the water flows
- Water-driven pounder: The same principle with a pestle; at Onta, in Ōita, such pounders still crush clay

## Requires

- [Stone Tools](https://lastcodex.org/en/inventions/stone-tools/): The first cutting edge (3.3 million years ago)
- [Plain bearing](https://lastcodex.org/en/inventions/plain-bearing/): A shaft turning on a film of lubricant (c. 4,700 BCE)

## Sources

- [添水 (sōzu), entries of the Seisen-ban Nihon Kokugo Daijiten and the Digital Daijisen](https://kotobank.jp/word/%E6%B7%BB%E6%B0%B4-552641), Shogakukan, via Kotobank
- [The Soundsilence of Water](https://kyotojournal.org/gardens/the-soundsilence-of-water/), Gunter Nitschke, Kyoto Journal (2011)
- [添水唐臼 (water-powered grain pounder)](https://www.shikokumura.or.jp/guide/facilities/water-powered-rice-mill/), Shikoku Mura open-air museum, Takamatsu
- [Shisendo](https://www.japan.travel/en/spot/1159/), Japan National Tourism Organization
- [Shisen-do Jozan-ji](https://www.discoverkyoto.com/places-go/shisen-do/), Discover Kyoto
- [添水 (Digital Daijisen; Kigo and Kidai Dictionary, Nichigai Associates)](https://www.weblio.jp/content/%E6%B7%BB%E6%B0%B4), Weblio
- [Gunsho ruijū, vol. 7 (1899), book 154: Zoku Mon'yō wakashū, miscellaneous poems (poem on the sōzu by the priest Kyōkaku)](https://dl.ndl.go.jp/pid/1879496), National Diet Library Digital Collections
- [Shiryō sōran, vol. 5 (1933): entry recording the completion of the Zoku Mon'yō wakashū (Kagen 3, 1305)](https://dl.ndl.go.jp/pid/1125786), Historiographical Institute, Tokyo Imperial University, via National Diet Library Digital Collections
- [ガッタリとは (the gattari, a water-driven pounder; the karausu of Onta pottery)](https://www.pref.miyagi.jp/soshiki/oksgsin-ns/noudou-gattari04.html), Miyagi Prefectural Government
- [Ontayaki no Sato](https://metropolisjapan.com/ontayaki-no-sato/), Metropolis Japan

Fact-checked on 2026-10-19.

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The Last Codex · https://lastcodex.org/en/inventions/water-scarecrow/ · © The Last Codex. Texts, plates and figures: CC BY-NC-ND 4.0.