A Kanban board is a tool used to manage work at a personal or organizational level by visually depicting work at various stages of a process using cards to represent work items and columns to represent each stage of the process. Cards are moved from left to right to show progress and to help coordinate teams performing the work. A Kanban board may be divided into horizontal "swimlanes" representing different kinds of work or different teams performing the work. The simplest Kanban board consists of three columns: "to-do", "doing" and "done", though some additional detail such as WiP (Work in Progress) limits are needed to fully support the Kanban Method.

Kanban boards can be used for knowledge work or manufacturing processes. They can be easily customized to match a teams own workflow and specific needs. Kanban boards can be used to organize many areas of an organization and can be designed accordingly. Business functions that use Kanban boards include software development teams, sales teams, and service teams.

The key components of a Kanban board include visual signals, columns, work-in-progress limits, a commitment point, and a delivery point. Visual signals are cards that represent work items and are placed into columns on the board. Columns represent the value stream, which is a sequence of specific steps that tasks or products must go through from the start of work to finish. Work-in-progress limits are used to limit the amount of work in progress at any given time. A commitment point is where work is committed to the team, and a delivery point is where work is delivered to the customer.

Kanban boards are used to optimize the flow of work, limit work-in-progress, and maximize efficiency. They help teams commit to the right amount of work and get it done. Kanban boards are flexible and customizable, so teams can adjust their board design as their process evolves. They are a perfect tool for visualizing potential problems in a process and for discouraging teams from multitasking by applying WIP limits according to their capacity.

In summary, a Kanban board is a visualization tool used to manage work at a personal or organizational level by visually depicting work at various stages of a process using cards to represent work items and columns to represent each stage of the process. It is a flexible and customizable tool that can be used to optimize the flow of work, limit work-in-progress, and maximize efficiency.