Uguisu-bari no Ishidatami

 “Uguisu-bari no Ishidatami” refers to the stone steps and flagstone pavement on the approach to the Mori Family Cemetery in Yamaguchi City’s Kozan Park. When you clap your hands or stomp your feet on the stone pavement, you can hear a mysterious sound similar to the chirping of a Japanese nightingale.

Where does the sound come from?

The cause of the mysterious sound seems to be the stone steps. As it turns out, it is caused by sounds being reflected from the stone steps. To give you a better understanding, please see the diagram (Figure 1) below. As shown, when standing on the stone pavement, (standing at some distance from the stone steps) clapping your hands in the direction of the stone steps will create a reflected sound.
In the example below (Figure 1), the time it takes for the sound wave to reach each step is different. As a result, the reflected sound wave from R1 to R4 gradually returns with a delay. The delay is determined by the width of the staircase. As a result, the sound waves (marked R1 to R4) overlap and form a continuous sound wave.

Figure 1

When these continuous sound waves reach our ears, they sound strange to us.

You can also hear the mysterious sound near the other stone staircase off to the far right!

Here are some other ways to enjoy it.

Mirror reflection:
As shown in the figure below, two people facing each other should stand on opposite sides of the stone-paved pathway, in front of the stone steps, while standing about an equal distance away from the stone steps. When you clap your own hands, you will not hear any reflected sound. But when your partner claps their hands, you will hear it! This phenomena can be explained in the following way. Imagine that you are standing in the same, current positions. Only this time, if a mirror is placed on the stone steps you would see your partner’s reflection in the mirror, but not your own reflection. The reflection of sound follows the same principle.
Change in frequency: From the same position, try clapping your hands while moving away from each other, so that the distance between the two of you gradually increases. The frequency of the mysterious sound you hear will become higher and higher. This can be attributed to the narrowing of the interval between the successive sound waves, as shown in the diagram above.

As shown in the figure below, two people facing each other should stand on opposite sides of the stone-paved pathway, in front of the stone steps, while standing about an equal distance away from the stone steps. When you clap your own hands, you will not hear any reflected sound. But when your partner claps their hands, you will hear it! This phenomena can be explained in the following way. Imagine that you are standing in the same, current positions. Only this time, if a mirror is placed on the stone steps you would see your partner’s reflection in the mirror, but not your own reflection. The reflection of sound follows the same principle. 

   Change in frequency: From the same position, try clapping your hands while moving away from each other, so that the distance between the two of you gradually increases. The frequency of the mysterious sound you hear will become higher and higher. This can be attributed to the narrowing of the interval between the successive sound waves, as shown in the diagram on the Figure 1.

日本語説明サイトはこちら

★This page was created based on research conducted in 2014-2015 by the following students from the Department of Physics and Information Science, Faculty of Science, Yamaguchi University:

• • Yuta Kojima (3rd year)
  • Yuhei Nawa (3rd year)
  • Ippei Hamamoto (3rd year)
  • Takumi Okamura (2nd year)
  • Kazuma Tani (2nd year)

English Translation: GLASSIC, Brian

Supervision and Contact Information 　

• Faculty of Science, Yamaguchi
  University1677-1 Yoshida, Yamaguchi City, Yamaguchi Prefecture
  753-8512
  +81-83-933-5700
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