Kanban is a Japanese word, which means ‘Visual Card’. It was
implemented by Taiichi Ohno in Toyota production system. He got this idea from
a grocery store, where he saw that keeper restocked the store based on
inventory and not on the basis of supply from the supplier. He used this
concept to maintain the inventory with demand. It is used as a signal in the
manufacturing process, where the workers will send what they need and in which
amount they need to the warehouse by simply writing in the Kanban card. It is simply a card, which gives complete
information about the product in a much simpler way. A simple example of kanban
card is shown in the figure below
Four basic principles of Kanban
1. to get the idea about the process – this means you first understand the process
that is existing. Kanban doesn’t say to change the current process without
2. Agree to small changes – this means that whenever there
is a small change due to Kanban, support it. The reason is, Kanban is a tool
that clears problem or guide you to the success through small changes rather
than abrupt changes.
3. Respect the current scenario – When one implements Kanban
in the current process, it does not tell you to change the whole process, but
to make the small changes in the current process which does not add value to
the process. And it does not tell you to change the steps that adds value to
the process. So, one must respect the current process, roles and
responsibilities of the whole system.
4. Encourage all – Since it is a tool of improvement and it
involves all, ideas must flow from all directions and they must be respected.
Ideas can come from any of the team members rather than just the management
Six general practices of kanban
Visualize the work flow
down every step from beginning to the end of the process and create a column or
line(lane) for each step.
down tasks separately on a physical card.
the types of tasks for easier visualization with the help of the colour codes.
from left to do to right done as shown in figure below.
Limit the work flow
Do not do such task which cause harm to your
process efficiency at a single time. There needs to be a limit, where only a
particular task needs to be done to reduce waste and improve the efficiency.
limits on columns in which work is being performed.
goal of WIP limits are smooth workflow and waste elimination.
always be based on measurements, so find and apply methods.
Use the gathered data to
adjust your process to maximize flow and efficiency.
steps, you will be able to identify where your tasks needs to be adjusted, and
what works best for you and your team.
Make policies explicit
The team must form the basic rules on the flow
of different items, when and how to note.
This needs to be marked on the board.
For the continuous improvement, meetings must be
carried out weekly or at the end of the shift to check whether work flow is
going as per the flow or not.
Feedback is necessary as it will indicate if
anything needs the improvement or is going well.
Collaborate for improvement
It requires the involvement of all departments,
rather than just one.
It is a team effort.
Rules of kanban by Toyota production system
are 6 rules defined by the Toyota production system: –
processes withdraw the items in the exact amount mentioned by Kanban.
produces items in precise amounts and sequences given by Kanban.
items should be moved or produced without kanban.
Kanban cards must accompany each and every time
with the parts.
and incorrect amounts should never be sent to the next downstream process.
number of Kanban cards is reduced carefully to minimize inventory and find the problems.
Types of kanban cards
are two principal types of Kanban cards:
kanbans also known as “move cards” are used to signal when a part is
ready to move from one lane to another lane in the manufacturing areas. The
card is attached with a prescribed number of parts, which are moved to the work
area that needs them. Once the parts are used, the card is returned as a signal
to send the same number of the same part back. An example of withdrawal Kanban card
is shown in figure
A kanban that
contains a comprehensive list of everything the part requires in order to be
completed is called the production kanban. This includes the parts required,
the materials required and the information included on a withdrawal kanban.
Importantly, a production kanban orders the production system to start with the
production of parts required in the production area. An example of production Kanban
card is shown in figure
addition, other types of Kanban cards that exists are:
come into use when the shortages of parts occur, to indicate the need for more
of a particular part or material so that the manufacturing process does not get
stopped and work flows smoothly. These are also sometimes known as signal
kanbans. Essentially, they are used to trigger purchases.
kanbans are used to replace the defective parts or to signal a sudden change in
the amount of product that are needed to be produced. Unlike express kanbans,
emergency kanbans are utilized when a part does not function like it is
supposed to or when the conditions of production changes.
It is a combination of withdrawal and production kanbans, and are used
when the two work areas for these kanbans are located close to each other, in
order to speed up production. For instance, if the storage area for components
is right next to the place where the product is assembled, having a single
kanban to pull the parts and run them through the production process saves
A supplier kanban is for the supplier – that sells materials to the
manufacturer and enters the supplier’s kanban system as a representative of the
manufacturer. They receive the card with the number of parts or raw material
required by the manufacturer.