Karl Scotland

While the word Kanban comes from the Japanese for “visual card”, the term
Kanban as used by the Kanban Software Development community, represents much more than a standard task-board. Additionally, the Kanban Software
Development community have not tried to replicate the mechanism of the
Toyota Production System kanban tool exactly, but have taken the underlying
principles in order to achieve similar effects in software development. So
what is a Kanban System for Software Development?

A Kanban System visualises some unit of value. This unit of value could be a User Story, Minimal Marketable Feature, Plain Old Requirement or something else. This is different from a task-board, which generally focuses on visualising the current tasks.

A Kanban System manages the flow of these units of value, through the use of Work In Process limits. This is different from a task-board, which generally has no WIP limits, but aims to have all tasks complete by the end of a time-box.

A Kanban System deals with these units of value through the whole system,
from when they enter a teams control, until when they leave it. This is
different from a task-board, which generally only deals with the work in the build/test stage, but shows no information about what work is being
prepared, or what work is ready for release.

By putting these 3 properties of a Kanban System together, we can describe a Kanban System for Software Development as one which allows value to flow
through the whole system using WIP limits to create a sustainable pipeline
of work. Further, the WIP Limits provide a mechanism for the Kanban System
to demonstrate when there is capacity for new work to be added, thereby
creating a Pull System. Finally, the WIP Limits can be adjusted and their
effect measured as the Kanban System is continuously improved.

A task-board simply shows what development tasks have been predicted to be done in the current time-box, with their status.

Torbjörn Gyllebring

To help us win as a team

Kanban to promotes flow and reduced cycle-time by limiting WIP and pulling value through in a visible manner.

Eric Willeke

Short

Kanban helps our team contribute to the business by promoting flow and reducing cycle-time through a limited WIP and a fully transparent value pulling system.

Shorter

Kanban is a transparent work-limited value pulling system.

Troy Tuttle

Value Pull, Limited WIP, and Visibility can create an ecosystem where teams have the opportunity to improve.

David Anderson

I think the underlying principles are that a fixed WIP limit provides a predictable cycle time and an expectation of a quality level. That a pull system balances demand against throughput, releasing slack time in non-bottlenecks and revealing the bottleneck in the process.

2ndary stuff comes from identification of bottlenecks, waste and variability and the three bodies of knowledge on what to do about them.