also: ろばのはし
noun
pons asinorum; donkey bridge; learning hurdle
A metaphor for a difficult obstacle in learning, especially a concept that blocks progress until it is understood. The term comes from the Latin 'pons asinorum' (bridge of donkeys), originally referring to a geometry theorem. In Japanese, it is a direct translation used in educational or philosophical contexts.
この定理は多くの学生にとってロバの橋だ。
This theorem is a pons asinorum for many students.
ロバの橋を越えれば、その先の学習が楽になる。
Once you get past the donkey bridge, the rest of the learning becomes easier.
難関 is a general term for a difficult barrier or obstacle, while ロバの橋 specifically refers to a conceptual hurdle in learning, often with a classical or academic nuance.
Calque from Latin 'pons asinorum' (bridge of donkeys), a term used in medieval logic and geometry for a difficult proof or concept that separates capable students from those who struggle. The Japanese form is a direct translation, likely introduced through Western educational texts.