ISTQB definition:
Kanban comes from an approach to working in manufacturing at Toyota. It is a way of visualizing work and workflow. It was developed by Taiichi Ohno, an industrial engineer at Toyota, and takes its name from the colored cards that track production and order new shipments of parts or materials as they run out. The tasks are put on sticky notes which are moved from left to right through the columns (like an assembly line for cars).
Human language:
The Kanban Method gets its name from the use of kanban – visual signaling mechanisms to control work in progress for intangible work products. The Kanban Method is flow – reflecting that work flows continuously through the system instead of being organized into distinct timeboxes.
Toyota's manufacturing rules are:
Each process issues requests (kanban) to its suppliers when it consumes its supplies;
Each process produces according to the quantity and sequence of incoming requests;
No items are made or transported without a request;
The request associated with an item is always attached to it;
Processes must not send out defective items, to ensure that the finished products will be defect-free;
Limiting the number of pending requests makes the process more sensitive and reveals inefficiencies.
Kanban is part of an approach where the pull comes from demand, and products are made to order. Re-supply or production is determined according to customer orders. Limits on the number of items waiting at supply points are established and then reduced as inefficiencies are identified and removed. Whenever a limit of inventory is exceeded, it points to an inefficiency that needs to be addressed. In contexts where supply time is lengthy and demand is difficult to forecast, often the best one can do is to respond quickly to observed demand.
The same happens with Kanban in Agile Development Kanban in an Agile process - is never restricted to a set process and defined sprint backlog. Therefore, it offers flexibility for developers. The method allows organizations to start with their existing workflow and drive evolutionary change. The workflow consists of logical steps.
One of the main goals of Kanban is to limit the buildup of excess inventory at any point on the production line, as well as extra work in the development process. Limits are set on the number of tasks to be completed, and new tasks are added and started only after completing the previous ones.
To gather relevant processes within a single workspace or task board area and to visualize work it goes through a Kanban Board uses. The Kanban board provides a simple way to understand the process and consists of Kanban Cards.
Kanban Cards - are key components of kanban is, in effect, a message that signals a depletion of product, parts, or inventory. Kanban cards live within lists and represent the most minute, detailed action items needed to complete the list. These cards are the specific items that must be addressed in sequential order to complete the list.
As you see from the image - all cards are our list of items. A Kanban board has columns for different stages of work, from the initial idea through the development and testing stages to the final delivery to users. There are two steps to a workflow, which are a queue and a work in progress. The team in charge decides on the maximum amount of work each step of the workflow can hold. Work is pushed into the queue step and pulled into the process step. Problem areas are highlighted by measuring the lead time and cycle time of the full process and process steps.
Kanban can span more than one team’s work (as opposed to Scrum). If user stories are grouped by feature, work may span more than one column on the Kanban board, sometimes referred to as swim lanes.
To enable real-time demand signaling across the supply chain, electronic kanban systems have become widespread. These systems leverage digital kanban boards, lists, and cards that are common. In various software systems, kanban is also used for signaling demand to suppliers through email notifications. When the stock of a particular component is depleted by the quantity assigned on the kanban card, a "kanban trigger" is created (which may be manual or automatic), and a purchase order is released with a predefined quantity for the supplier defined on the card, and the supplier is expected to dispatch material within a specified lead-time. Kanban - helps to optimize the flow of tasks between different teams and have own practices, principles, and values.
Kanban Principles
Start with what you do now: The team must understand current processes as they are actually practiced and respect existing roles, responsibilities, and job titles;
Agree to pursue improvement through evolutionary change: After starting with the existing process, the team must agree on continuous, incremental, and evolutionary changes;
Encourage acts of leadership at every level: Kanban does not expect leadership from a specific set, rather the actions of leadership at all levels in the organization, are very much encouraged;
Understand and focus on your customers’ needs and expectations: Organizations are a collection of interdependent services, and place the focus on the work, not the people doing the work;
Manage the work; let people self-organize around it: There are no roles explicitly called for when adopting Kanban.
Kanban Practices
Visualize: Kanban process visualizes the workflow which is easy to understand. The process must be shown step by step using visual cues that make each task clearly identifiable. The idea is to clearly show what each step is, what expectations are, and who will take what tasks. These tasks would then be placed into swim lanes, defined sections that group related tasks to create a more organized project;
Limit work in progress: A key principle of Kanban is to have a limit for work-in-progress activities. As kanban is rooted in efficiency, the goal of kanban is to minimize the amount of work in progress. Teams are encouraged to complete prior tasks before moving on to a new one. This ensures that future dependencies can be started earlier and that resources such as staff are not inefficiently waiting to start their task while relying on others. A company must internally assess the appropriate amount of WIP to be carrying as it works through the kanban process. This is often tied to the number of people along the process. If we concentrate on one task, we are much more efficient at doing it, so this approach is less wasteful than trying to do little bits of lots of different tasks;
Implement feedback loops: Those feedback loops (cadences) are:
Strategy Review (Quarterly);
Operations Review (Monthly);
Risk Review (Monthly);
Service Delivery Review (Bi-Weekly);
Replenishment Meeting (Weekly);
The Kanban Meeting (Daily);
Delivery Planning Meeting (Per Delivery Cadence);
Manage flow: Sometimes, limitations are not met or goals are not achieved; in this case, it is up to the team to manage the workflow and better understand the deficiencies that must be overcome. The flow of work in service should maximize value delivery, minimize lead times and be as predictable as possible. Transparency, inspection, and adaption uses in order to balance these potentially conflicting goals;
Make policies explicit: Explicit policies help explain a process beyond just the listing of different stages in the workflow. Policies should be sparse, simple, well-defined, visible, always applied, and readily changeable by the people working on the service;
Improve collaboratively, and evolve experimentally: Kanban applies continuous and incremental improvement instead of trying to reach a predefined finished goal. Whenever teams have a common understanding of concepts about work products, they enhance actions that could achieve the goal.
Kanban values
Transparency;
Balance;
Collaboration;
Customer Focus;
Flow;
Leadership;
Understanding;
Agreement;
Respect.
There are no roles explicitly called for when adopting Kanban
The function of understanding the needs and expectations of customers and facilitating the selection and ordering of work items is often filled by a product manager, product owner, or service manager. Responsible for the flow of work to deliver select items to customers is Service Delivery Manager.
Kanban became an effective tool to support running a production system as a whole, and an excellent way to promote improvement. Successful implementation of kanban may lead to reduced expenses, greater customer satisfaction, more efficient processes, and minimized risk due to unforeseen problems.
Companies that use kanban practices may also have greater predictability for what's to come. But Kanban relies on stability, a company must have a predictable process that cannot materially deviate. For companies operating in dynamic environments where activities are not stable, the company may find it difficult to operate using Kanban.
Conclusion:
So, if you are asked at an interview: What is Kanban? The best way to answer is:
Kanban comes from an approach to working in manufacturing at Toyota.
The Kanban Method gets its name from the use of kanban – visual signaling mechanisms to control work in progress for intangible work products. The Kanban Method is flow – reflecting that work flows continuously through the system instead of being organized into distinct timeboxes. To gather relevant processes within a single workspace or task board area and to visualize the work it goes through, a Kanban Board uses. The Kanban board provides a simple way to understand the process and consists of Kanban Cards.
Kanban Cards - are key components of kanban is, in effect, a message that signals a depletion of product, parts, or inventory. Kanban cards live within lists and represent the most minute, detailed action items needed to complete the list. Kanban - helps to optimize the flow of tasks between different teams and have own practices, principles, and values.