Items often get blocked midstream awaiting external review, dependencies, questions, approvals, or other input from outside the team. For my Xbox teams, this happens most often at the Implement step. To handle the issue, we add a Track column to the middle of the Implement step. Items are moved to the Track column whenever they are blocked awaiting external input. Tracked items don’t count toward the Implement WIP limit. We talk about their status during every daily standup until they are unblocked. When a tracked item is unblocked, it moves back to the Active column as soon as a slot becomes available. The logic is that any item already in Implement has higher priority than the next item from Specify. (I talk about other ways to handle late or unstable dependencies in Chapter 7, “Using Kanban within large organizations.”) Occasionally, it becomes apparent that an item will be blocked indefinitely. We have a special area for those items in the corner of the signboard. We call it the “parking lot.” Every few weeks, we check on the status of parking lot items, but we don’t do this daily.