When a man came in the middle of the night, he returned home after hearing that she was asleep; the following morning, on learning what had happened, she composed this in response to the man’s explanation.
ふしにけりさしも思はゞ笛竹の音をぞせまし夜更けたりとも
| Fusinikeri sasi mo omoFaba Fuetake no oto wo zo semasi yo Fuketari tomo |
‘Tis true I was abed; Yet if you’d shown some thought, A bamboo flute, You would have blown, Though the night was lightening! |
Izumi Shikibu
和泉式部
Is there a pun here on ふしにけり (was lying in bed) and ふし (a joint of bamboo; a melody) ?
Yes. I think this would be categorised as engo (‘evocative language’) rather than as a pun as such, but the effect is the same.