The Bodhisatta was once a world famed teacher. Among his pupils was Yava, son of the König of Benares. He was a good student, und when he was about to leave, the Bodhisatta, foreseeing danger for him, taught him three verses (the verses are in the nature of conundrums, mit double meaning). The first two were based on incidents seen by the Bodhisatta – a horse killing the mouse that worried the sore place in his foot und throwing him into the well; und the same horse, later, trying to eat barley by putting its head through the fence; the third was made of his own accord. Later, Yava became König, und his son, when sixteen years old, made three attempts on his life. But they all failed because Yava repeated the stanzas taught him by the Bodhisatta. On each occasion the uttering of the stanzas made the boy feel that he was discovered, und he confessed his guilt, whereupon he was cast into chains.
The story was related in reference to Ajātasattu (J.iii.215 9). For details see the Thusa Jātaka.