A kotowaza to encourage exploration and growth.
(I no naka no kawazu taikai wo shirazu;
“The frog in the well knows not the great ocean.”)
A frog at the bottom of a well may look up and see only walls and a circle of sky; it may look around and think that the cistern it lives in is the whole world, or all of the world that matters. It doesn’t know about the vastness of the world outside, or about the oceans that dwarf its little pool – and as a result, it may gain an overinflated view of its own importance.
This saying thus has two, related uses. It can point to a situation where someone has limited access to information, or a narrow worldview. Or it can mean someone who has a lot of pride in their knowledge – but only because they know so little that they don’t realize how much there is that they don’t yet know. In either case, the implication is critical, with a nuance that the ignorance the person displays is at least in part due to their own sense of self-importance preventing them from seeking deeper or broader knowledge. I like to twist the saying in a positive direction by suggesting that a frog brought out of the well can learn about the ocean and benefit from the experience.
井 (i, pronounced like the letter “e” in English) is a water-well. 中 (naka) is another noun, indicating the inside or middle of something. 蛙 is yet another noun, “frog.” Note that in this case the usual pronunciation, instead of standard-Japanese kaeru, is kawazu – a poetic or archaic name for “frog.” These three nouns are joined with the associative particle の (no), for a literal rendition along the lines of “frog of middle of well.” This noun phrase forms the subject of the sentence.
The predicate is simply an object-verb grouping: 大海 (taikai) is literally “large sea,” or “ocean.” を is our object-marker particle, and 知らず is an archaic or formal negative form of 知る (shiru), “to come to know.”
Despite kawazu being the more common reading, kaeru is also acceptable. 井の中 can be replaced with 井底 (seitei, “the bottom of a well”). The character 中 can be replaced with 内 (uchi, “inside”) without any change in meaning. The whole saying may be referred to, shorthand, as just 井の中の蛙 or even 井蛙 (seia, “well-frog”).
(“Daigaku wo sotsugyou shi, furusato ni modori, tokui ni natteiru hito wo mitara, yahari i no naka no kawazu taikai wo shirazu to omowazaru wo emasen deshita.”)
[“After graduating from university, returning to my hometown, and seeing the people there putting on airs, I couldn’t help but think about how the frog in the well knows nothing of the ocean.”]