Kanban focuses on continuous flow guided by the Lean methodology. It has five core principles, which are: visualize the workflow, limit work-in-process, manage the flow, make process policies explicit, and improve collaboratively. The last three principles are built on the first two. A vital piece is the visual workflow, commonly implemented as a "card wall". This can be a physical or digital wall displaying index cards or sticky notes with columns representing different states of the workflow. Limiting the work-in-process is also essential in maintaining order and balance within the columns. Kanban's encouragement of continuous flow lends itself to small, continuous, incremental changes.
Scrum and Kanban lead to the evolution of Scrumban. Combine the two approaches and receive a sum that is larger than its parts. When implementing Kanban it stipulates to "respect the current process, roles, responsibilities, and titles." This lends itself to simple integration with existing systems; furthermore, Scrum and Kanban both champion continuous process improvement and self-organizing teams. The big question is, "Can these two ideas coexist?"
The rise of Scrum and Kanban in recent years is part of a continuous journey by the software development industry. Its quest is to find the best solution to increase output and decrease waste while providing better visibility and higher overall success. Other methods such as waterfall, prototyping and unified process strive towards the same goal. Each company's staff and culture are different. A one-size-fits-all approach to product management is unrealistic. The success of a methodology lays within the people and implementation.