How to Read “夕立は馬の背を分ける”
Yuudachi ha uma no se wo wakeru
Meaning of “夕立は馬の背を分ける”
This proverb expresses how localized rain such as evening showers falls within such a narrow range that even in very close locations, there is a clear division between places that get wet from rain and places that don’t.
Specifically, it is used to explain the meteorological phenomenon where evening showers caused by cumulonimbus clouds have a limited rainfall range with very clear boundaries. In reality, you can witness scenes where one side of a road is experiencing heavy rain while the opposite side has no rain at all.
The reason for using this expression is to convey the characteristic of evening showers’ localized nature in a way that anyone can easily understand. By using the concrete and familiar length of a horse’s back, it impressively expresses how sharp the rain’s boundary can be. Even today, it is sometimes used in weather forecasts to explain guerrilla downpours and localized rain, and it is cherished as an expression that conveys the mystery and fascination of natural phenomena.
Origin and Etymology
The origin of “Evening shower divides horse’s back” comes from expressing the characteristic way summer evening showers fall. Evening showers are localized rain caused by cumulonimbus clouds, and the natural phenomenon of their extremely narrow rainfall range forms the background of this expression.
This expression was born from the fact that even within the short distance of a horse’s back, situations actually occur where one side is beaten by heavy rain while the other side doesn’t get wet at all. Similar expressions can be found in Edo period literature, showing that people had been paying attention to the localized nature of evening showers since that time.
The expression “divides horse’s back” is a clever metaphor that uses the familiar and concrete length of a horse’s back to express the sharpness of rain boundaries. Horses were the main means of transportation at the time and were among the most familiar animals to people. Therefore, the sense of distance equivalent to a horse’s body length was easy for anyone to imagine and likely made it easy for this proverb to become established.
This expression demonstrates the sharpness of observation in accurately capturing meteorological phenomena unique to Japanese summers, and tells the story of the richness of Japanese people’s expressive power in comparing natural phenomena to familiar things.
Interesting Facts
Raindrops from evening showers are larger than those of regular rain, sometimes reaching 4-5 millimeters in diameter. This is because the strong updrafts of cumulonimbus clouds cause raindrops to move up and down repeatedly within the cloud, allowing ice particles to grow before melting and falling.
Meteorologically, the rainfall range of evening showers is extremely narrow at only a few kilometers in diameter, and because their movement speed is also fast, they often pass through in just 15 to 30 minutes. This characteristic forms the basis of the natural phenomenon that gave birth to the expression “divides horse’s back.”
Usage Examples
- Just a while ago the shopping district over there was experiencing a downpour, but we didn’t get wet at all over here – truly “Evening shower divides horse’s back”
- The east exit of the station has a heavy rain warning while the west exit is sunny – “Evening shower divides horse’s back” is well said indeed
Modern Interpretation
In modern society, the proverb “Evening shower divides horse’s back” has come to hold new meaning. Now that weather forecast accuracy has improved and the term “guerrilla downpour” has become established, this proverb is used as a metaphor to express various aspects of modern society beyond simply explaining natural phenomena.
In the information society, this proverb is also applied when expressing “information gaps” and “digital divides.” Even when living in the same area, the phenomenon where large disparities arise in the information obtained due to differences in internet environments and information literacy can truly be called a situation that “divides horse’s back.”
Also, with the spread of social media, the phenomenon of “information localization” where people are exposed to completely different information about the same event can be expressed with this proverb. As a result of algorithms delivering information optimized for individuals, modern people are bathing in completely different “information rain” from the person next to them.
Economically too, while globalization advances, regional disparities are expanding, and phenomena can be seen where prosperous districts and declining districts are clearly divided even within the same city. This can also be understood as a modern version of a situation that “divides horse’s back.”
When AI Hears This
The reality of evening showers captured by modern weather radar perfectly embodies the situation of “dividing a horse’s back.” Cumulonimbus clouds have an average diameter of 2 to 5 kilometers. This scientifically explains the phenomenon where neighboring towns experience torrential rain while here it remains clear.
Particularly fascinating are the topographical conditions that make evening showers likely to occur. On mountain slopes, the “orographic lifting effect” causes air heated during the day to rush up the mountainsides, with temperature dropping approximately 0.6 degrees for every 100 meters of elevation gained. This temperature differential causes cumulonimbus clouds to develop rapidly. In fact, evening showers frequently occur in the foothills of Okutama and Tanzawa in the Kanto Plain, while they often don’t fall in the urban center.
Even more remarkable is the similarity to modern guerrilla downpours. Due to the urban heat island effect, central Tokyo becomes 2 to 3 degrees hotter than surrounding areas. This “artificial mountain” effect generates localized torrential rain through the same mechanism as the topography-induced evening showers of old.
According to Japan Meteorological Agency radar analysis, evening showers move at speeds of 20 to 40 kilometers per hour. This is almost exactly the speed of a horse running at full gallop. Without any scientific data, the ancients had perfectly identified the nature of this “moving wall of rain.”
Lessons for Today
“Evening shower divides horse’s back” teaches modern people that situations can differ greatly even in nearby places. What the person next to you is experiencing might be completely different from what you are experiencing.
This realization gives us an important perspective for deepening understanding of others. Even in the same workplace or the same family, the situations each person is placed in are more different than we think. By developing the habit of thinking from the other person’s standpoint, better communication will emerge.
Also, this proverb teaches us wisdom for living in modern society with its rapid changes. Situations might be localized and temporary. Even if you’re in a difficult situation now, it’s not permanent, and if the place or time changes slightly, a completely different development might be waiting.
Learning from the wisdom of our predecessors who expressed life’s subtleties through natural phenomena, we should live each day with a flexible perspective.
Comments