In 1950, Toyota was a struggling Japanese car company.
American manufacturers like Ford and GM were giants. They had scale, capital, technology.
Toyota had none of that.
But they had something else: Kaizen.
改善 (kai = change, zen = good)
Continuous improvement.
Not big, dramatic changes. Not revolutionary breakthroughs.
Just small improvements. Every day. By everyone.
Over decades, those small improvements compounded into dominance.
By 2008, Toyota became the world’s largest automaker.
The philosophy that got them there? Kaizen.
And it’s as relevant to software as it is to manufacturing.
What Is Kaizen?
Kaizen is a philosophy: Everyone, every day, should make things a little bit better.
Not “let’s have a big improvement initiative.”
But “let’s improve this one thing right now.”
The Core Principles
1. Small changes, not big transformations
- Don’t wait for permission to improve
- 1% better every day compounds to huge gains
2. Everyone participates
- Not just managers or engineers
- Assembly line workers, janitors, everyone
3. Continuous, not episodic
- Not “improvement quarter”
- Improvement is the job, every day
4. Process-focused, not results-focused
- Fix the process, results follow
- Don’t optimize metrics, optimize the system
5. Respect for people
- The people doing the work know it best
- Listen to front-line workers
How Toyota Does It
1. The Andon Cord
On Toyota’s assembly line, there’s a cord above every workstation.
Any worker can pull it to stop the entire line.
Not managers. Not engineers. Any worker.
Why this matters:
In traditional factories, stopping the line is forbidden. It costs money. Workers are punished for slowing production.
Toyota’s philosophy:
Better to stop the line and fix the problem now than ship defects.
Real example:
A worker noticed that a bolt was hard to reach. It slowed her down by 3 seconds per car.
She pulled the andon cord.
Response:
- Line stops
- Team investigates
- Redesign workstation layout
- Bolt is now easier to reach
- Line restarts
Result: Every car from now on is assembled 3 seconds faster. Forever.
Cost: 10 minutes of stopped production.
Payoff: Infinite.
The lesson:
Empower people closest to the work to fix problems immediately.
2. Gemba Walks
“Gemba” (現場) = “the real place”
The practice:
Managers regularly go to the factory floor. Not to inspect. To learn.
What they do:
- Watch the work
- Ask questions (not accusatory, genuinely curious)
- Listen to workers
- Identify waste and problems
What they don’t do:
- Give orders
- Criticize
- Stay in their office
Example:
An executive notices workers walking back and forth to get tools.
Traditional response: “Work faster.”
Kaizen response: “Why are tools far away? Can we move them closer?”
Result: Reorganize workspace. Tools within arm’s reach. Workers more efficient.
3. 5 Whys
When a problem occurs, ask “Why?” five times to find the root cause.
Example:
Problem: Production line stopped.
Why? Machine overheated.
Why? Not enough lubrication.
Why? Lubrication pump failed.
Why? Pump filter was clogged.
Why? No one checked the filter.
Root cause: No maintenance checklist for filters.
Solution: Add filter check to weekly maintenance routine.
Traditional approach stops at “machine overheated.” Fix the machine, move on.
Kaizen digs deeper. Fix the system so it doesn’t happen again.
4. Standardized Work
The idea:
Document the current best way to do every task.
Not to lock in the process forever.
But to create a baseline for improvement.
Why this works:
If everyone does things differently, you can’t improve the process.
With a standard:
- Everyone does it the same way
- You can measure performance
- You can experiment with changes
- You can tell if the change is better
Then update the standard.
Key point: Standards are living documents, not commandments.
5. Kaizen Events
What it is:
A focused, short-term improvement project.
Structure:
- Duration: 3-5 days
- Team: Cross-functional, including front-line workers
- Goal: Improve one specific process
- Deliverable: Implemented change by end of week
Example:
Problem: It takes 45 minutes to change dies on a stamping press (downtime = lost production).
Kaizen event:
- Day 1: Observe current process, map steps
- Day 2: Identify waste, brainstorm improvements
- Day 3: Test new approach
- Day 4: Refine and document
- Day 5: Train everyone, implement
Result: Die change now takes 15 minutes.
Key insight:
Not a “study group” or “committee.” You implement by end of week.
Kaizen in Software Development
Toyota’s principles apply directly to software:
1. Continuous Refactoring
Kaizen mindset:
Don’t wait for “refactoring quarter.” Improve the code every time you touch it.
The rule:
Leave the code slightly better than you found it.
Example:
You’re adding a feature. You notice:
- A function is poorly named
- Some duplication
- Missing tests
Don’t: “I’ll file a ticket for later.”
Do: “I’ll fix it now. Takes 5 minutes.”
Compounding effect:
Every developer improves code they touch = codebase improves continuously.
2. Stop the Line (CI/CD)
Toyota: Pull the andon cord to stop production.
Software: Break the build? Stop everything. Fix it immediately.
Practice:
- CI/CD pipeline fails? Drop everything, fix it
- Production bug? Stop feature work, fix it
- Security vulnerability? Immediate focus
Why:
Don’t accumulate technical debt. Fix problems when they’re small.
3. Blameless Postmortems (5 Whys)
When something breaks:
Traditional: “Who screwed up?”
Kaizen: “What in our process allowed this to happen?”
Example:
Incident: Deployed code that crashed production.
5 Whys:
Why did the code crash? Null pointer exception.
Why wasn’t it caught in testing? Test coverage didn’t include that edge case.
Why didn’t tests cover it? Developer didn’t think to test it.
Why didn’t the developer think of it? No checklist for edge cases.
Why is there no checklist? We haven’t documented common failure modes.
Solution: Create a checklist of common edge cases to consider. Update it whenever we discover new ones.
Not: “Fire the developer.”
But: “Improve the system.”
4. Standardized Work (Style Guides, Patterns)
Kaizen approach:
Document current best practices. Update as you learn.
Examples:
- Coding standards (documented, updated quarterly)
- Architecture patterns (living docs)
- Deployment runbooks (refined after each deploy)
Anti-pattern:
“We don’t need docs, everyone just does it their own way.”
Result: Can’t improve what isn’t consistent.
5. Gemba Walks (Code Reviews, Pair Programming)
Traditional code review:
“Approve or reject.”
Kaizen code review:
“What can we learn from this? How can we improve our practices?”
Questions:
- Is there a pattern we should document?
- Is there duplication we can eliminate?
- Is there a test case we should add to our standard suite?
Pair programming = Gemba:
Learn by observing the work happening.
6. Small, Frequent Improvements (Feature Flags, A/B Tests)
Kaizen:
Small changes, tested, iterated.
Anti-pattern:
Big bang releases. Months of work. “Launch and pray.”
Better:
Ship small changes. Measure. Iterate.
Example:
Want to improve conversion rate?
Don’t: Redesign entire checkout flow at once.
Do:
- Change button color → measure
- Simplify one form field → measure
- Add progress indicator → measure
- Each change is small, reversible, measurable
Compound small wins.
Why Kaizen Is Timeless
Management fads come and go.
Agile. Scrum. OKRs. Holacracy. Squads and Tribes.
Kaizen has lasted 70+ years because it’s not a methodology. It’s a mindset.
It’s Universal
Kaizen applies to:
- Manufacturing
- Software
- Healthcare
- Education
- Your personal life
Because the principle is simple: Improve a little, every day.
It’s Sustainable
Big transformations burn people out.
“We’re doing a complete rewrite!” “We’re reorganizing everything!” “We’re switching to a new framework!”
Kaizen is the opposite.
Small, continuous improvements are sustainable.
It Compounds
1% improvement per day = 37x better in a year.
1.01^365 = 37.78
Most companies:
Try to improve 50% in one quarter, fail, give up.
Kaizen companies:
Improve 1% continuously. Win over time.
It Respects People
Kaizen says: The people doing the work know the work best.
Not: “Executives will design the perfect process.”
But: “Front-line workers will improve the process.”
This is empowering and effective.
Common Mistakes When Adopting Kaizen
Mistake 1: Kaizen Theater
What it looks like:
- “We’re doing Kaizen now!”
- Create suggestion box
- Hold monthly “improvement meetings”
- Nothing changes
What’s missing:
Kaizen isn’t a program. It’s a daily habit.
Mistake 2: Top-Down Improvement
What it looks like:
- Management decides what to improve
- Workers implement management’s ideas
- No ownership
What’s missing:
Improvements should come from the people doing the work.
Mistake 3: Metrics Over Process
What it looks like:
- “Increase velocity by 20%!”
- Pressure on metrics
- Gaming the numbers
What’s missing:
Kaizen focuses on improving the process. Better process → better results.
Don’t optimize the scoreboard. Optimize the game.
Mistake 4: No Time for Improvement
What it looks like:
- “We’re too busy shipping features to improve”
- Improvement is “extra” work
- Technical debt accumulates
What’s missing:
Improvement IS the work.
Toyota: Assembly line workers spend 10% of their time on improvement.
Software equivalent: Engineers spend time on refactoring, tooling, automation.
Mistake 5: Blame Culture
What it looks like:
- Worker pulls andon cord → gets yelled at
- Bug in production → “Who did this?”
- Mistake = punishment
What’s missing:
Kaizen requires psychological safety.
If people fear blame, they won’t surface problems.
How to Start Kaizen in Your Team
Week 1: Identify One Pain Point
Don’t try to fix everything.
Ask the team: “What’s one annoying thing we deal with every day?”
Examples:
- Slow CI/CD pipeline
- Flaky tests
- Confusing deployment process
- Hard-to-find documentation
Pick one.
Week 2: 5 Whys
Dig into the root cause.
Don’t just patch the symptom.
Example:
Pain: CI takes 30 minutes.
Why? Too many tests.
Why? Tests aren’t parallelized.
Why? Test runner doesn’t support parallelization.
Why? We chose a simple test runner 3 years ago.
Root cause: Tooling choice didn’t scale.
Solution: Migrate to test runner with parallelization.
Week 3: Experiment
Run a small experiment.
Don’t try to perfect it. Try something.
Example:
- Migrate 10% of tests to new runner
- Measure impact
- Learn
Week 4: Standardize or Iterate
Did it work?
- Yes → Document new standard, migrate rest
- No → Try something else
Key: Move fast. Learn fast.
Month 2 and Beyond: Repeat
Pick next pain point. Improve.
Make it a habit.
Real-World Kaizen Wins
Example 1: Amazon’s Two-Pizza Teams
Small teams = easier to improve continuously.
Large teams = coordination overhead kills improvement.
Kaizen applied: Optimize team size for velocity of improvement.
Example 2: Etsy’s Deployment Pipeline
Etsy used to deploy once a week. It was painful.
Kaizen approach:
- Made small improvements to deployment process
- Automated one manual step at a time
- Improved observability incrementally
Result: Now deploy 50+ times per day. Each improvement compounded.
Example 3: Spotify’s “Hack Weeks”
Engineers spend 10% of time on improvements (not features).
Kaizen applied: Dedicated time to make the system better.
Example 4: Your Team
Small Kaizen wins you can start today:
- Add one more test to flaky suite
- Document one confusing process
- Refactor one ugly function
- Automate one manual task
Each one takes 30 minutes.
Each one makes tomorrow better.
Key Takeaways
- Kaizen = Continuous improvement by everyone, every day
- Small changes compound into huge gains
- Empower people closest to the work to improve it
- Fix processes, not people
- Stop the line when there’s a problem
- Standards are baselines for improvement, not rigid rules
- Improvement is part of the work, not extra work
- Timeless because it’s a mindset, not a methodology
Toyota didn’t beat Ford and GM with better technology.
They beat them with better culture.
A culture where:
- Every worker has permission to improve
- Every day is an opportunity to get better
- Every small improvement compounds
Software is no different.
You don’t need a big transformation.
You need continuous improvement.
Pick one thing. Make it a little better. Tomorrow, pick another.
That’s Kaizen.
And it works.