One Piece Flow, also known as Single Piece Flow or Continuous Flow Manufacturing, is a lean manufacturing principle that emphasizes the production of one unit at a time through each step of a production process. This approach, a cornerstone of lean methodologies, aims to minimize waste, enhance efficiency, and improve product quality. It is a stark contrast to traditional batch-and-queue production systems, where items are processed in large batches, often resulting in delays, bottlenecks, and higher inventory levels.