How to Read “身から出た錆”
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Meaning of “身から出た錆”
“Rust that came out from body” means falling into a difficult situation due to one’s own actions or character.
This proverb expresses that the cause of problems or misfortune lies not externally, but within oneself. It is used when someone suffers disadvantages due to their own words and actions, poor judgment, or character flaws. For example, when a person who habitually lies loses trust, or when someone with a lazy personality misses important opportunities.
The reason for using this expression is to clarify where responsibility lies. Rather than attributing things to bad luck or blaming others, it has the effect of making people recognize that the fundamental cause lies within themselves. Even today, it is often used when expressing the concept of self-responsibility, and is effectively utilized in situations that encourage reflection and introspection. This proverb teaches us the importance of first examining ourselves for problem-solving.
Origin and Etymology
The origin of “Rust that came out from body” is based on ancient knowledge about sword maintenance. In Japan, swords have long been considered the soul of the samurai, and their maintenance was extremely important work. The cause of rust forming on sword blades actually lies in the iron content of the sword itself. Rust occurs when the iron in the sword reacts with moisture and oxygen in the air, but this is not external contamination—it’s a phenomenon that occurs when the sword’s own components change.
From this phenomenon came the expression “Rust that came out from body.” Swordsmiths and samurai understood through experience that the cause of rust was not on the outside of the sword, but due to the sword’s own properties. From there, it’s believed that the same way of thinking came to be applied to human behavior as well.
Since this expression can be found in Edo period literature, it seems to have been established as a common proverb at least several hundred years ago. It can be said to be an expression filled with wisdom based on actual experience, unique to Japan where sword culture was deeply rooted. It’s also a proverb that tells of the keen observational skills of the Japanese people, who overlaid the properties of metal with principles of human behavior.
Interesting Facts
Rust on swords actually progresses not just on the surface, but deep into the blade. Completely restoring a rusted sword to its original state is extremely difficult, and even skilled swordsmiths struggle with this work.
Interestingly, modern psychology also has a concept called “internal attribution,” which is very similar to the thinking behind “Rust that came out from body.” The thought pattern of attributing the results of one’s actions to internal rather than external factors is said to lead to self-growth.
Usage Examples
- His getting fired from the company was rust that came out from body, because he was always late
- When you’re always speaking ill of others and then lose all your friends, that’s truly rust that came out from body
Modern Interpretation
In modern society, “Rust that came out from body” has come to have more complex meanings. With the spread of social media, past statements and actions remain as digital records and can become problems at unexpected times. Cases where careless posts from student days become disadvantageous during job hunting, or where past statements by celebrities become the cause of online backlash, can truly be called modern versions of “Rust that came out from body.”
On the other hand, in modern society, the need to distinguish between individual responsibility and structural social problems has also increased. For example, there are many social factors that cannot be solved through individual effort alone, such as economic disparity and inequality in educational opportunities. Therefore, when applying the concept of “Rust that came out from body,” careful judgment is required to determine whether it’s truly individual responsibility or a social problem.
Also, in modern times with deeper understanding of mental health, excessive self-responsibility theory is sometimes viewed as problematic. It’s not appropriate to dismiss mental health issues like depression as “weakness” or “character problems.” The original value of this proverb lies in encouraging constructive self-reflection, not in continuously blaming oneself.
Even in modern times, the basic attitude of taking responsibility for one’s actions remains important. However, it’s crucial to practice this while maintaining empathy for others and understanding of society.
When AI Hears This
When we examine the mechanism of iron rusting, a truly fascinating fact emerges. Rust is actually iron oxide, formed when iron undergoes a chemical reaction upon contact with oxygen and moisture. In other words, oxygen and water—absolutely essential for living organisms—become the “source of destruction” for iron.
This contradictory structure bears a striking resemblance to human self-destruction patterns. For example, talent that should bring success breeds complacency, leading to neglect of effort and eventual failure. Love becomes overprotection, hindering the growth of those we care about. Wealth generates luxury, dulling judgment and inviting ruin.
From a scientific perspective, rust progresses gradually from the surface inward, ultimately robbing the metal of its fundamental strength. Human self-destruction follows the same pattern—small moments of carelessness and arrogance accumulate until, by the time we notice, the situation has become irreversible.
What’s even more intriguing is that preventing rust requires “moderate management.” Completely blocking oxygen renders metal useless, but proper rust prevention treatment ensures longevity. The same applies to humans—rather than completely eliminating the elements of success, it’s crucial to maintain balance with “rust preventatives” like humility and self-control.
Lessons for Today
“Rust that came out from body” teaches modern people that true growth begins with facing oneself. When problems arise, it’s natural human reaction to want to first blame the environment or other people. However, real solutions often lie within ourselves.
This proverb doesn’t harshly demand self-responsibility. Rather, it teaches us that we have the power to create change within ourselves. While we cannot change external factors, we can change our own thinking and actions. That is the hopeful message this proverb carries.
In modern society, we increasingly compare ourselves to others on social media or harbor dissatisfaction with society’s unfairness. At such times, this proverb makes us think “What can I do first?” It reminds us that small daily choices eventually create major changes.
There’s no need to be perfect. What’s important is taking responsibility for our actions and maintaining an attitude of continuous learning from failures. By doing so, we can transform even “rust” into nourishment for growth.


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