The Heijunka board is used to plan the Heijunka (Japanese = measure level). It is a panel for visualizing and smoothing production. This board is used to control the sequence in which production orders are processed. In the board, which can also be displayed electronically, the cards that are due are inserted into the next free slots and processed as part of Kanban control.
Our tip: A heijunkaboard smoothes production, but increases inventory and thus also contributes to muda (Japanese = waste). So check exactly where you actually need such a board.