Lean production has two pillars. One is just-in-time (JIT), that is, just-in-time production. It doesn't use forecast or planned production, and only starts to organize production according to the product specification, quantity and delivery date of the order after receiving the customer order, so as to reduce the risk of overstocking of inventory funds and increasing the inventory of dull goods. Another pillar is automation (Jidoka). It is completely different from the traditional automation that pursues "high speed, large output and multi-purpose". It makes "adaptive, specialized and miniaturized" automatic machines at the lowest cost, so that large and small batches of products can be quickly manufactured and qualified.
Around these two pillars, Toyota has summarized a series of unique improvement technologies such as kanban production, standard operation and flat production. In fact, these technologies are still a bit rough. Toyota requires workers to realize this technology in finer details, and thus puts forward the basic concept of "Kaizen and continuous improvement" to eliminate visible waste to the greatest extent and invisible waste to the greatest extent.