a vein; a thread of connection
Used to describe a subtle but perceptible link, similarity, or underlying continuity between things, often in abstract contexts like ideas, styles, or atmospheres. Commonly appears in the phrase 一脈通じる (to have something in common).
There is a thread of connection between his work and his master's.
It seems there is a vein of connection between those two incidents.
have something in common; share a common thread
have something in common; share a common thread
Compound of 一 (one) and 脈 (vein, pulse), literally 'one vein'. The figurative sense of a connecting thread derives from the image of a single vein linking things.