Definition
Linking adjacent operations directly and passing one piece at a time with no inventory between them; it is the tightest of the three ways to connect operations in a value stream, alongside FIFO lanes and supermarket pull.
In detail
Continuous flow is about how operations are connected; one-piece flow is about how many pieces move at a time. The courseware often treats them as the same thing, and the difference is only the angle. Continuous flow has preconditions: the cycle times of the adjacent operations must be under takt, quality must be stable and changeovers short, or linking them just makes them stall each other. When that is impossible, step back to a FIFO lane, and only then to supermarket pull — the order cannot be reversed, because each step back adds a layer of inventory. To judge whether a segment is continuous flow, look for an inventory triangle in between.
Example in practice
Three operations with cycle times of 18, 20 and 19 seconds against a 22 second takt are linked directly into one cell and the racks between them are removed. The fourth operation still needs a 120 minute changeover and cannot be linked yet, so a FIFO lane is placed in front of it.