馬鹿の一つ覚え
Meanings
1
a fool's one trick; one who knows little often repeats it
Proverb used to criticize someone who keeps repeating the same limited knowledge or skill, often inappropriately. Literally 'a fool's one memorized thing'.
He keeps telling the same story like a one-trick pony.
Like a fool with one trick, he tries to solve everything with that method.