When I first collaborated with a Japanese engineering team, I was perplexed. Pull requests took a long time to merge, comments were extremely detailed and sometimes overly picky, and no one gave an immediate LGTM. However, I decided to take a closer look.
It wasn’t inefficiency—it was discipline. Japanese engineers don’t just review code; they respect it. Let’s explore how Japanese developers approach code reviews and why it’s advisable to learn from them.
1. It’s Not About Speed. It’s About Safety.
In Western teams, speed is prioritized: push fast, fix fast, and move forward. But in Japan, pushing broken code is considered highly irresponsible. Therefore, reviews are conducted slowly and deliberately. Each line is scrutinized like a contract, with engineers asking if it is the simplest possible implementation, if it matches the intended architecture, and what would happen if the code runs for five years.
Example: A Typical PR Review Comment in Japan
– const timeout = 1000;
+ const timeout = 1000; // TODO: Move to config?
// Comment:
// “Please avoid magic numbers. Let’s extract this to a config constant or ENV variable. Hardcoded values can cause hidden bugs later during scaling or infra migration.”
2. Review Is a Part of Design — Not Just Debugging
In many teams, the sequence is design first, code next, review last. However, in Japanese teams, review is integrated into the design process. The reviewer checks if the code aligns with the domain model, draws diagrams, suggests better separation of concerns, and flags classes that feel off.
Example: Sample Class Diagram (UML)
Imagine you’re building a ride-hailing service. A Japanese reviewer might expect you to adhere to domain boundaries like this:
+——————-+ +——————+
| RideRequest |<>—–>| Rider |
+——————-+ +——————+
| – origin | | – name |
| – destination | | – contactInfo |
| – requestTime | +——————+
| – status |
+——————-+
|
| depends on
v
+——————-+
| DriverMatch |
+——————-+
| – driverId |
| – eta |
| – fareEstimate |
+——————-+
A reviewer would question if DriverMatch should really be inside RideRequest and if this coupling would remain effective if the process for assigning drivers changes.
3. Junior Devs Learn From Every Review
In Japan, code review acts as mentorship. The tone remains respectful, and reviewers explain why something is wrong, not just what is wrong. They might share links to documentation, send book excerpts, or write small proofs of concept to clarify ideas. Comments may include:
– Array.prototype.some(callback)
+ for (let i = 0; i < arr.length; i++) {
if (callback(arr[i])) return true;
}
// Comment:
// "I know .some() works, but explicit iteration is easier to debug and might be safer in legacy environments. Also helps new grads understand what’s happening under the hood."
Though this approach slows things down, it helps develop robust engineers over time.
4. Conflict Is Handled Silently — But Clearly
Unspoken rule: Never publicly embarrass someone. If a major flaw is found, it’s addressed privately. Disagreements are handled quietly and precisely, which promotes deeper, calmer discussions and reduces bruised egos.
5. There’s a Strong Focus on Future Engineers
Japanese teams review code with future engineers in mind, considering if the next person will understand it and if it can be maintained over time. They avoid clever hacks unless absolutely necessary.
Code Example: Avoiding “Smart” Shortcuts
// Clever, but cryptic
return !!(flags & 0x4);
// Instead
return isFlagEnabled(flags, FLAG_IS_ELIGIBLE);
// With helper function:
function isFlagEnabled(flags, bitMask) {
return (flags & bitMask) !== 0;
}
This style is slower to write but easier to maintain, especially given team rotations common in Japan.
So What Can We Learn?
You don’t need to become slow or hierarchical to adopt this mindset. Value the long game by making comments thoughtful, focusing on design, reviewing like a teacher, and respecting the next engineer. The Japanese approach can delay delivery and sometimes be overly cautious. However, it results in reliable, maintainable, and quietly beautiful codebases, which is valuable in a world that often rushes to move fast and break things.
Final Thoughts
Working with Japanese engineers changed how I write and review code. It taught me that good engineering isn’t always loud; sometimes, the best code is the one that no one has to rewrite. Next time you review a PR, pause, read slowly, ask questions, and perhaps leave a comment as they would in Tokyo.