Time-boxing allows us to employ a very powerful aspect of Kanban. The cards in each column represent capacity for each stage of the value stream. As we see above, each stage can only handle one zone at a time. That is the capacity of each stage, if we have one person working at each stage.

Time-boxing is the first step in beginning to find a balanced flow for our value stream as visualized on our Heijunka board. However, one problem exists. Each stage of effort in the stream will require a different length time-box. This can cause gaps and pileups.

For example, if our level designer can lay out a level in a week, but the high res artist requires two weeks, then a lot of work can pileup for the high res artist. Conversely, if the concept artist requires two weeks to complete the concept art for each zone, the level designer might be waiting for work with nothing to do. We have to find ways to balance this workflow smoothly so that everyone has work to do every day. One way of doing this is to balance the effort on each stage to achieve the same flow through the system.