- When I was younger,
I lived in a large subdivision
with one swimming pool.
In the mid-western states,
the pool season is short,
usually only about two months.
So within those months,
all the kids in the subdivision
would try and pour into the shared pool.
On a warm day, the pool would become chaotic
and swell into a stew of laughing and screaming kids.
The pool managers had to come up with a solution
to fight this avalanche.
So one day, they introduced a new system.
Each kid was given a red elastic bracelet.
They were told to put this bracelet on their left wrist.
Once the bracelets ran out,
new kids had to wait outside the pool
for someone else to exit.
I didn't notice it at the time,
but I was taking part in a kanban system.
The pool had a set capacity.
The number was written in bright blue
right next to the lifeguard.
It could handle 120 kids at one time.
So the managers purchased 120 red elastic bracelets.
The managers also had to deal with unpredictability.
A rainy day could easily turn sunny
and then the pool would fill up
in less than an hour.
Some kids could stay all day
while others came in for just a quick swim.
There were no ways to create rules
to manage the whole system.
So instead, there were only two simple rules.
You had to be wearing a red bracelet,
and once the bracelets ran out,
you had to wait.
Fast forward to today,
and the same rules can apply to the workplace.
A kanban team has a set capacity.
This is usually the number of hours
each person works in a week.
So five team members might each have a capacity
of 35 hours a week.
That means that the whole team
will have a set capacity of 175 hours.
It's just like the pool sign
hanging right next to the lifeguard,
except instead of 120 kids,
you now have 175 hours.
Like the pool managers,
kanban teams have to deal with a lot of uncertainty.
There could be a huge rush of work one week,
then the next week might be quieter.
Some tasks might take months to finish,
while others could be completed in an afternoon.
The biggest difference with kanban teams
and the swimming pool
is what each team decided to use
for a signaling device.
The pool managers had each kid
wear a red bracelet.
Where kanban teams typically use cards
or even post-it notes.
In fact, the word kanban is Japanese for signal card.
It signals to everyone
whether you're active in the system.
If you're wearing a red bracelet,
then it means that you're active in the system.
When you give that bracelet up,
it means that there's an opening
for someone else to enter the system.
It's the same way with your kanban team.
A signal card shows what's active in the system.
When you finish that card,
it means that there's room for another card
to enter the system.
One thing to keep in mind
is that the real strength in kanban is its simplicity.
You shouldn't always assume
that complex problems require complex solutions.
Sometimes, simple solutions are powerful.
They're easier for people to accept
and they can be elegant and long-lasting.