Survival Japanese for Developers at Japanese Tech Companies 2026 — Keigo, Code Review, Meetings, Incidents, 1on1 Vocabulary Deep Dive

• Intro: 2026, the Year Japanese Tech Finally Opened Up to Foreign Engineers
• 1. Greetings: Otsukaresama desu vs Otsukaresama vs Gokurousama
• 2. The Politeness Ladder: Shouchi vs Ryoukai vs Kashikomarimashita
• 3. Asking for Something: Gokakunin Onegai Shimasu / Yoroshiku Onegai Itashimasu
• 4. Slack/Chatwork Etiquette Vocabulary
• 5. Code Review: The Japanese Version of the LGTM Ladder
• 6. Meeting Types: Meeting vs Uchiawase vs MTG vs Asakai vs Yuukai
• 7. Gijiroku (Meeting Minute) Template
• 8. Furikaeri (Retrospective): KPT and YWT
• 9. QA / Testing: Tantai, Ketsugou, UAT, Regression
• 10. Bug Reports: Saigen Tejun, Kitaichi, Jissokuchi
• 11. Incident Response: Shougai-Taiou Vocabulary
• 12. 1on1, Evaluation, OKR Vocabulary
• 13. JTC vs Mega-Venture: Industry Geography Vocabulary
• 14. Katakana IT Vocabulary Dictionary
• 15. Nijuu Keigo (Double Honorifics) — the Politeness Trap
• 16. Direct-Translation Traps: Iken / Goiken / Okangae
• 17. English-to-Japanese IT Term Mapping
• 18. Emoji and Stamp Culture
• 19. Email Formality Mastery: External vs Internal
• 20. Soft Refusal and Disagreement
• 21. The Apology Ladder
• 22. Time Expressions: Kigen, Shimekiri, Deadline
• 23. Joining and Leaving: Naitei, Nyuusha, Taishoku, Enman Taisha
• 24. Learning Roadmap: How to Grow Your Japanese IT Vocabulary
• References

Intro: 2026, the Year Japanese Tech Finally Opened Up to Foreign Engineers

The 2026 Tokyo/Osaka tech hiring market is more open to foreign engineers than ever. Mercari has run on English as the in-house language for over five years. LINE, now under the NAVER-SoftBank joint structure, mixes Korean, Japanese, Taiwanese, and Thai engineers daily. ZOZO, CyberAgent, PayPay, Rakuten, DeNA — all pushed foreign engineer ratios into double-digit percentages, and full-remote senior reviewers in Seoul approving Tokyo HQ pull requests are no longer a rarity.

The catch is the gray zone: "code is global but meetings are Japanese, the wiki is Japanese, and Slack mentions are Japanese." Even at English-meeting companies, lunch chat, 1on1s, and the incident Slack channel still flow in Japanese. And the first time you mistype "otsukaresama desu" the room goes quiet for five seconds.

This guide is for non-Japanese engineers surviving a Japanese IT company (or Japanese subsidiary). It covers 24 scenarios with Japanese example sentences, romaji, English meaning, and the timing of when to use each. It is not a vocabulary list; the goal is cultural calibration — what impression each tone leaves.

1. Greetings: Otsukaresama desu vs Otsukaresama vs Gokurousama

The most-heard and most-confused greeting. A literal "thanks for your hard work," but in Japan the choice depends on time of day, hierarchy, and channel (text vs spoken).

A common mistake: at modern companies like Mercari or LINE you do not need to prefix every Slack message with "otsukaresama desu" — jumping straight into the body is considered efficient. But at JTC (Japanese Traditional Company) shops like Rakuten or NTT Data, the greeting at every message is still the norm.

2. The Politeness Ladder: Shouchi vs Ryoukai vs Kashikomarimashita

The single English word "understood" splits into 4-5 Japanese tiers. A Korean engineer who only knows "ryoukai desu" can sound flippant to senior staff.

Tip: the view that "ryoukai" is rude toward superiors is a relatively recent urban legend (originating in 2010s manner books). Mercari does not care; financial-sector clients still expect "shouchi shimashita."

3. Asking for Something: Gokakunin Onegai Shimasu / Yoroshiku Onegai Itashimasu

PR merge requests, doc reviews, data confirmations — "please confirm" makes up 80% of Japanese business communication.

A common pitfall: literally translating "please confirm" as "kakunin onegai shimasu" without the "go-" prefix sounds slightly command-like. Always attach "go-" to make it "gokakunin onegai shimasu."

4. Slack/Chatwork Etiquette Vocabulary

[Slack message example - polite]
お疲れさまです、@田中さん。
決済APIの障害の件、再現手順を共有させていただきます。
お手数ですが、ご確認いただけますでしょうか。

1. /payments/v2/charge にPOST
2. amount = 0 を含めると500エラー
3. ログは添付の通り

何卒よろしくお願いいたします。

[Slack message example - casual (Mercari style)]
@tanaka 決済APIのバグっぽいの見つけました、見てもらえますか?
- amount=0 で500
- ログ: thread
お願いします!

Frequently used Slack vocabulary:

Tip: "naru haya" is informal in-house lingo — never use it in email. Slack and Chatwork only.

5. Code Review: The Japanese Version of the LGTM Ladder

In Japanese dev culture, "LGTM" in English is common, but mixing in Japanese phrasing for senior reviewers or external partners feels more natural.

Shiteki vs Teian: "shiteki" (指摘, pointing out) is read as a strong word in Japanese review culture. "Teian" (提案, suggestion) or just "comment" lands more softly.

[Code review comment examples]
# Soft tone (suggestion)
こちらの関数名、`fetchUser` よりも `getUserById` の方が分かりやすいかもしれません。
お時間ある時にご検討ください。

# Standard tone (change request)
こちらの実装ですが、null のケースが考慮されていないように見えます。
ガード句を追加していただけますでしょうか。

# Strong tone (blocker)
こちらはセキュリティ上の問題があるため、マージ前に修正をお願いいたします。
具体的には、ユーザーのメールアドレスがログに出力されています。

# LGTM
LGTM です。マージしていただいて結構です。

# Praise
このリファクタリング、とても読みやすくなりました。素晴らしいです!

6. Meeting Types: Meeting vs Uchiawase vs MTG vs Asakai vs Yuukai

In Japanese companies, the single word "meeting" splits into five or more Japanese words.

Tip: "uchiawase" carries the nuance of "several people gathering to coordinate" — typically 2-5 attendees rather than 1-on-1.

7. Gijiroku (Meeting Minute) Template

Meeting minutes are core to Japanese company culture. Even foreign engineers, when hosting a meeting, may be asked to write the minutes in Japanese.

# 議事録: 決済システムv2 設計レビュー

## 日時
2026/05/16 (金) 14:00〜15:00

## 参加者
- 田中(PdM)、佐藤(EM)、金(BE)、Lee(QA)

## アジェンダ
1. v2 アーキテクチャ概要
2. マイグレーション計画
3. リスクと対応策

## 決定事項
- マイグレーションはBlue-Green方式で実施
- 期限: 2026年Q3末
- オーナー: 金

## ToDo
- [ ] @金 詳細設計書作成 (期限: 5/30)
- [ ] @佐藤 SREチームとキャパシティ調整 (期限: 5/23)
- [ ] @Lee QA計画策定 (期限: 6/6)

## 次回
2026/05/30 (金) 14:00〜

Minutes vocabulary:

8. Furikaeri (Retrospective): KPT and YWT

The most commonly used retro frameworks in Japanese IT teams.

KPT retro
- K (Keep): things to keep doing
- P (Problem): problems
- T (Try): things to try next

YWT retro (Japan-native)
- Y (Yatta koto): what we did
- W (Wakatta koto): what we learned
- T (Tsugi yaru koto): what to do next

Fun/Done/Learn
- Fun: what was fun
- Done: what got done
- Learn: what we learned

Tip: hiragana "furikaeri" feels softer; kanji "furikaeri" lands more formal in documents. Both are correct.

9. QA / Testing: Tantai, Ketsugou, UAT, Regression

Test types are sometimes loanwords, but JTC-leaning companies prefer the kanji forms.

Tip: "QA passed" is phrased as "QA wo pasu shita" or "QA OK ga deta."

10. Bug Reports: Saigen Tejun, Kitaichi, Jissokuchi

The Japanese bug report template is nearly standardized across companies.

# バグレポート: 決済API 500エラー

## 概要
amount=0 を含むリクエストで500エラーが返る

## 再現手順
1. POST /api/v2/payments
2. body に amount=0 を含める
3. 500エラーが返る

## 再現性
100% (10/10回)

## 期待値
400 Bad Request エラー、メッセージは "amount must be greater than 0"

## 実測値
500 Internal Server Error、スタックトレース添付

## 環境
- 本番環境 (production)
- API version: v2.3.1
- 発生日時: 2026/05/15 14:23 JST

## 影響範囲
全ユーザーの amount=0 リクエスト (約 3% / day)

## 暫定対応
クライアント側で amount > 0 のバリデーションを追加 (5/15 リリース済み)

## 恒久対応
サーバー側でバリデーションを実装 (Issue #1234)

Core vocabulary:

11. Incident Response: Shougai-Taiou Vocabulary

[Slack #incident channel example]
[14:23] 田中: @here 決済APIで500エラー多発中、調査開始します
[14:25] 田中: ステータス: 確認中 (調査中)
[14:31] 田中: 原因: DBコネクションプール枯渇の可能性、リソース確認中
[14:42] 田中: 暫定対応: 該当インスタンスを再起動、エラー率は0.1%まで低下
[14:55] 田中: 復旧確認、モニタリング継続
[15:30] 田中: 完全復旧確認、インシデントクローズ
[翌日] 田中: ポストモーテム書きました → [link]

Incident vocabulary:

Tip: "kirimodoshi" is the native Japanese term for rollback, common at JTC firms. Modern companies like Mercari and LINE just say "roorubakku."

12. 1on1, Evaluation, OKR Vocabulary

The 1on1 has become standard at modern Japanese IT companies. Some vocabulary overlaps with Korean usage but diverges in nuance.

Tip for non-Japanese engineers: "hyouka" carries a heavier weight than the English "evaluation." Asking "how is my hyouka going?" in a 1on1 sounds blunt. "Konki no fiidobakku wo itadakemasu ka" ("could I get feedback on this period?") lands much more naturally.

13. JTC vs Mega-Venture: Industry Geography Vocabulary

A trap to know: the Japanese IT industry is structured around SI, SES, and multi-tier subcontracting. Targeting in-house product companies (Mercari, LINE, CyberAgent) is the common career move — "never go to SI" is treated as folk wisdom.

14. Katakana IT Vocabulary Dictionary

Tip: even in Japanese-language meetings, 30-50% of nouns are katakana. Sentences like "agile ni sprint wo mawashite refactoring wo deploy" flow naturally.

15. Nijuu Keigo (Double Honorifics) — the Politeness Trap

Trying to be too polite and over-stacking honorifics creates awkward Japanese. Non-native speakers fall here often.

Rule: "sasete itadaku" is a strong humble form. Do not attach it to already-humble verbs like "ukagau / haiken suru / moushiageru."

16. Direct-Translation Traps: Iken / Goiken / Okangae

Tip: in English we use imperatives ("please reply"); in Japanese we soften with question or conditional forms like "itadakemasu deshou ka" / "itadakemasu to saiwai desu."

17. English-to-Japanese IT Term Mapping

18. Emoji and Stamp Culture

In Japanese-company Slack and Chatwork, emoji and stamp use is not decorative — it is a core piece of business communication.

Tip: at Mercari and LINE, a senior can reply to a junior's message with just a thank-you stamp and that is taken as a polite enough response. At JTC firms a text reply is still the baseline.

19. Email Formality Mastery: External vs Internal

[External customer email - formal]
株式会社XXX
田中様

いつもお世話になっております。
株式会社YYYの金です。

決済システムv2の件、添付の通り設計書を共有いたします。
ご確認のほど、よろしくお願いいたします。

ご不明な点がございましたら、お気軽にお問い合わせください。

何卒よろしくお願い申し上げます。

---
金 영주 (Kim Youngju)
株式会社YYY バックエンドエンジニア
youngju@yyy.co.jp

[Internal Slack to colleague - casual]
@田中 v2の設計書できました!
↓ docs/design-v2.md
時間ある時に見てもらえると嬉しいです
お願いします!

Email vocabulary:

20. Soft Refusal and Disagreement

A direct "no" is almost never used in Japanese business culture. Soft refusal phrases are essential.

Tip for non-Japanese engineers: "kentou shimasu" in a Japanese meeting is 90% rejection. Translating "this is hard given the schedule" directly as "schedule-teki ni muri desu" is too strong. "Schedule-teki ni kanari muzukashii joukyou desu" lands more naturally.

21. The Apology Ladder

Tip: "sumimasen" doubles as apology, thanks, and a way to flag attention. It is not strong enough for a real business apology — default to "moushiwake gozaimasen."

22. Time Expressions: Kigen, Shimekiri, Deadline

23. Joining and Leaving: Naitei, Nyuusha, Taishoku, Enman Taisha

Tip: Japan expects 1-3 months of notice before resignation. The Korean style of "I am out next week" causes serious friction. Securing enough "hikitsugi kikan" (handover period) is critical.

24. Learning Roadmap: How to Grow Your Japanese IT Vocabulary

[3-month roadmap]
Month 1: Greetings and politeness ladder
- Master otsukaresama desu / shouchi shimashita
- Establish Slack/Chatwork formal register
- Write one gijiroku per week (even for English meetings)

Month 2: Code review and PRs in Japanese
- Write PR descriptions in Japanese
- Try Japanese in review comments
- Switch LGTM to kakunin shimashita

Month 3: Meeting facilitation and 1on1
- Try hosting asakai in Japanese
- Push 1on1 Japanese ratio to 50%
- Host a furikaeri session

Recommended learning resources:

References

• jisho.org - EN-JP / JP-EN dictionary
• Qiita - largest Japanese dev community
• Zenn - modern Japanese dev platform
• Mercari Engineering Blog
• LINE Engineering Blog
• DeNA Engineering
• Classmethod DevelopersIO
• Recruit Tech Blog
• News Google Japan - Tech
• The Japan Times - Tech section
• CyberAgent Developers Blog
• Yahoo! JAPAN Tech Blog
• GMO Tech Blog
• ZOZO Tech Blog