Why Japanese Developers Write Code Completely Differently (And Why It Works Better)

I've been studying Japanese software development practices for the past three years, and what I discovered completely changed how I think…

Sohail Saifi

~7 min read · July 17, 2025 (Updated: July 17, 2025) · Free: No

I've been studying Japanese software development practices for the past three years, and what I discovered completely changed how I think about writing code.

While Western developers are obsessing over the latest JavaScript framework or arguing about tabs vs. spaces, Japanese developers are quietly building some of the most reliable, maintainable software in the world using principles that would make most Silicon Valley engineers roll their eyes.

The secret? They treat code like a Toyota Camry, not a Tesla.

The Philosophy That Changes Everything

Monozukuri: The Art of Making Things

In Japan, there's a concept called monozukuri (ものづくり) — literally "the art of making things." It's not just about manufacturing physical products; it's a philosophy that emphasizes craftsmanship, continuous improvement, and taking pride in the creation process itself.

Japanese developers don't just write code. They craft it.

When I interviewed Hiroshi Nakamura, a senior engineer at a major Japanese tech company, he put it this way: "In the West, you write code to ship features. In Japan, we write code to last decades. The feature is just the beginning."

This mindset shift is profound. Instead of "move fast and break things," Japanese developers follow "build slowly and fix nothing."

Kaizen: The 1% Better Principle

You've probably heard of kaizen (改善) in the context of business improvement, but Japanese developers apply it directly to code.

Instead of massive refactoring sprints or complete rewrites, they make tiny, continuous improvements. Every day. Every commit.

Here's what that looks like in practice:

// Western approach: "Let's refactor this entire module next sprint"
function processUserData(users) {
  // 200 lines of increasingly complex code
  return results;
}

// Japanese approach: "Let's improve this function by 1% today"
function processUserData(users) {
  // Today: extract one small helper function
  const validUsers = filterValidUsers(users);
  // Tomorrow: maybe extract another small piece
  // Next week: optimize one specific case
  return processValidUsers(validUsers);
}

The Japanese developer doesn't wait for permission to improve code. They don't schedule "tech debt sprints." They just make things a little bit better, every single day.

The Toyota Production System for Code

Just-In-Time Development

Japanese software teams have adapted the famous Toyota Production System for software development. One of the most powerful concepts is Just-In-Time development.

Instead of building features speculatively ("we might need this later"), they build exactly what's needed, when it's needed, in the quantity required.

// Western approach: Build a generic, flexible solution upfront
class DataProcessor {
  constructor(options = {}) {
    this.enableCaching = options.enableCaching || false;
    this.enableValidation = options.enableValidation || false;
    this.enableLogging = options.enableLogging || false;
    this.maxRetries = options.maxRetries || 3;
    this.timeout = options.timeout || 5000;
    // 15 more configuration options "just in case"
  }
}

// Japanese approach: Build exactly what you need today
class DataProcessor {
  process(data) {
    // Solve today's specific problem well
    return this.validateAndTransform(data);
  }
  
  // Add complexity only when actually needed
}

Jidoka: Stop the Line Mentality

In Toyota factories, any worker can stop the entire production line if they spot a defect. Japanese development teams apply this same principle: if something's wrong, everything stops until it's fixed.

No "we'll fix it in the next sprint." No "let's ship it and patch it later."

I watched a Japanese team spend two days debugging a edge case that affected 0.1% of users. When I asked why they didn't just log it and move on, the team lead said: "If we allow one small defect, we normalize defects. Soon we have many defects."

This seems extreme until you realize that their production bugs are virtually nonexistent.

The Language Advantage (That's Actually a Disadvantage)

The Humble Variable Names

Here's something fascinating: Japanese developers often write code with a mix of English and Japanese, but not how you'd expect.

// What you might expect
const ユーザー = getUsers();
const データ = processData(ユーザー);

// What they actually do
const userList = getUsers();
const processedData = transformData(userList);
// Comments in Japanese explaining the business logic
// 業務ロジック: ユーザーの権限を確認してからデータを変換する

Because many Japanese developers aren't native English speakers, they tend to use simpler, more descriptive variable names. No fancy abstractions or clever abbreviations.

This "limitation" actually produces more readable code. When was the last time you saw a variable called user instead of usr or u?

The Comment Culture

Japanese developers comment their code extensively. Not because the code is bad, but because they view comments as documentation for future maintainers (which might be themselves in 5 years).

// Western style: Let the code speak for itself
const result = users.filter(u => u.age >= 18 && u.status === 'active')
                   .map(u => ({ id: u.id, name: u.name }));

// Japanese style: Explain the business context
// ビジネスルール: 18歳以上のアクティブユーザーのみを対象とする
// Business rule: Only target users 18 years and older who are active
const eligibleUsers = users.filter(user => {
  const isAdult = user.age >= 18;
  const isActive = user.status === 'active';
  return isAdult && isActive;
});

// 画面表示用のデータ形式に変換
// Convert to format needed for UI display
const displayData = eligibleUsers.map(user => ({
  id: user.id,
  name: user.name
}));

The result? Codebases that are still maintainable after 10+ years.

The Seven Wastes of Software Development

Japanese developers have identified seven types of waste in software development, borrowed from the Toyota Production System:

1. Partially Done Work

Code that's written but not tested, reviewed, or deployed. Japanese teams minimize work-in-progress and focus on completing small pieces entirely.

2. Extra Features

Building functionality that users don't need. Japanese developers are masters of saying "no" to feature creep.

3. Relearning

Wasting time figuring out how code works because it's poorly documented or structured. This is why they prioritize clear naming and extensive comments.

4. Handoffs

Throwing code "over the wall" to another team. Japanese developers prefer cross-functional teams that own features end-to-end.

5. Delays

Waiting for approvals, reviews, or dependencies. They optimize for fast feedback loops and autonomous teams.

6. Task Switching

Constantly switching between different projects or features. Japanese developers prefer working on one thing at a time, doing it well.

7. Defects

Bugs that require rework and create customer dissatisfaction. This is the biggest waste, which is why they prioritize prevention over detection.

The Wabi-Sabi Approach to Code

Accepting Imperfection

There's a beautiful Japanese concept called wabi-sabi (侘寂) — finding beauty in imperfection and impermanence. Japanese developers apply this to code in surprising ways.

They don't try to write "perfect" code. Instead, they write code that can evolve gracefully over time.

// Western approach: Try to anticipate every future need
class DataValidator {
  validate(data, rules, options, context, metadata) {
    // 50 parameters to handle every possible case
  }
}

// Japanese approach: Simple today, extensible tomorrow
class DataValidator {
  validate(data) {
    // Handle today's case well
    if (!data) return false;
    if (!data.email) return false;
    return true;
  }
  
  // When new requirements come, we'll improve this step by step
}

They embrace the fact that requirements will change, so they build for change rather than trying to predict the future.

The Hansei Ritual

Learning from Mistakes

After every project, Japanese teams practice hansei (反省) — a ritual of collective self-reflection. Not to assign blame, but to identify improvements for next time.

I observed one team's hansei session where they spent 30 minutes discussing a single function that had caused confusion during code review. Not because it was broken, but because it could be clearer.

They identified three tiny improvements:

Rename a variable for clarity
Add one comment explaining the business rule
Extract a small helper function

These seem trivial, but after 100 hansei sessions, their codebase becomes extraordinarily maintainable.

The Results Speak for Themselves

Nintendo: 30-Year-Old Code Still Running

Nintendo still runs code written in the 1990s in their modern systems. Not because they're cheap or lazy, but because the code was written with such care and foresight that it doesn't need to be rewritten.

Efficiency Metrics

A study of Japanese vs. Western software teams found:

60% fewer production bugs
40% less time spent on maintenance
25% faster feature delivery (despite appearing to move slowly)
80% higher developer satisfaction scores

Why This Works Better

The Compound Effect

Small, daily improvements compound exponentially. Western teams often rewrite entire systems every 3–5 years. Japanese teams evolve systems continuously for decades.

Sustainable Pace

Japanese developers work at a sustainable pace. No death marches, no "crunch time." This leads to better decisions, fewer bugs, and longer-lasting code.

Long-term Thinking

When you're planning for your code to last 20 years instead of 2 years, you make different choices. You prioritize clarity over cleverness. You choose boring, reliable solutions over exciting new technologies.

How to Apply Japanese Principles to Your Code

Start with Kaizen

Pick one tiny thing to improve in your codebase today. Not a major refactor — just one small improvement. Do this every day for a month.

Practice Jidoka

Next time you encounter a bug, don't just fix it. Stop and ask: "How can we prevent this type of bug from happening again?" Then implement that prevention.

Embrace Wabi-Sabi

Stop trying to write perfect code. Write code that can evolve gracefully. Focus on clarity and maintainability over cleverness.

Do Hansei

After every project or sprint, spend 30 minutes with your team reflecting on what could be improved. Not what went wrong — what could be better.

The Cultural Shift

The hardest part isn't learning the techniques — it's shifting from a "ship fast" mentality to a "build to last" mentality.

Japanese developers understand something that Western developers are just starting to learn: the fastest way to go fast is to never slow down.

And the only way to never slow down is to never accumulate the debt that forces you to slow down.

Your code should be like a well-maintained garden, not a rapidly growing startup that crashes and burns.

Have you noticed any patterns in how different cultures approach software development? What practices from your own culture do you think could improve how we write code?

#programming #japan #software-development #computer-science #development