Toyota Way

toyota-way — Toyota Way & TPS Reference

Toyota Production System (TPS) and Toyota Way concepts for software engineering. English-first. Japanese terms shown inline with kanji and reading.

Use when applying lean thinking, identifying waste, structuring problem-solving, or connecting the triz tool to Japanese management philosophy.

Scripts

Both scripts print a structured markdown template to stdout. Fill in bracketed fields. Both embed a triz solve invocation in the root cause section — run it if a contradiction emerges.

The two pillars

Just-in-Time — make only what is needed, only when needed, only in the amount needed. Eliminates inventory (work-in-progress), over-production, waiting.

Jidoka — 自働化 (じどうか) — autonomation with a human touch. The kanji 働 (human work) is deliberate — not 自動化 (pure automation). Machines detect defects and stop automatically; humans investigate before anything resumes. Two mandatory moves: autonomous detection, then human judgment. Neither alone is jidoka.

The three wastes

Muda — 無駄 (むだ) — waste. Unnecessary work, unused features, dead code, over-engineering. The target of most lean effort.

Muri — 無理 (むり) — overburden. Asking more than capacity allows. Context window exhaustion, sprints that require heroics, agents without timeouts.

Mura — ムラ (むら) — unevenness. Inconsistency, variability, flakiness. Non-deterministic builds, variable LLM output without temperature control, batch-and-queue workflows that create feast-or-famine load.

All three interact: muri creates mura, mura creates muda. Fix muri first.

Problem-solving tools

Poka-yoke — ポカヨケ (ぽかよけ) — mistake-proofing. Prevent errors before they occur rather than inspect them out afterward. Named from 馬鹿避け (fool-avoiding). The device makes the wrong action impossible, or immediately visible.

Software: type systems, required fields, merge gates, acceptance criteria checked before merge. Rust's borrow checker is poka-yoke. triz eval --ci is poka-yoke. Pairs directly with TRIZ Principle 11 (Beforehand Cushioning) — academic literature at P2SL Berkeley explicitly connects mistakeproofing to TRIZ inventive principles.

5 Whys — なぜなぜ分析 (なぜなぜぶんせき) — ask "why" five times to reach root cause. Each answer becomes the next question. Stop when you reach a cause you can actually fix. The analysis is complete when the root cause is a policy or system failure, not a person. Pairs naturally with TRIZ: 5 Whys finds the contradiction; TRIZ resolves it.

A3 thinking — A3思考 (えーさんしこう) — entire problem documented on one A3 sheet (420×297mm). Structured sections: background → current state → target → root cause analysis → countermeasures → acceptance criteria → follow-up. Toyota's PDCA (計画・実行・確認・改善, plan-do-check-improve) made visible and portable. Forces clarity: if it doesn't fit on one page, the thinking isn't clear yet.

Andon — 行灯 (あんどん) — the signal light showing production status. Origin: a paper lantern. Anyone on the line can pull the andon cord to stop production when they spot a defect. Stopping to fix is faster than passing defects downstream. Software: CI red build, triz eval exit 1, drift flag in council output.

Genchi genbutsu — 現地現物 (げんちげんぶつ) — "go and see." Go to the actual place (現地), observe the actual thing (現物). No decision without direct observation. Software: reproduce the bug locally before diagnosing, read the actual code before proposing a fix, run triz doctor before assuming the environment is healthy.

Strategy and alignment

Hoshin kanri — 方針管理 (ほうしんかんり) — policy deployment. Cascade organizational direction (方針) down to implementation through the whole structure. Sets the "what" at each level; teams determine the "how." The TRIZ Journal documents pairing with TRIZ: hoshin kanri defines the strategic contradiction to resolve; TRIZ finds the resolution; A3 documents it; the corpus records it.

Nemawashi — 根回し (ねまわし) — "going around the roots." Build consensus by consulting each stakeholder individually before the formal meeting. No surprises in the room; the decision is effectively made before the decision meeting. The formal meeting ratifies what nemawashi already achieved.

Ringi — 稟議 (りんぎ) — the formal written proposal circulated for sequential approval stamps (判子, hanko). Creates an accountability trail. Each stamp = explicit acknowledgment of responsibility. Software: the PR description as ringi document, required reviewers as hanko holders, merge as the final stamp.

Heijunka — 平準化 (へいじゅんか) — production leveling. Smooth out demand spikes; avoid batch-and-queue. Even flow over time beats maximum throughput followed by idle. Software: steady spec dispatch over waves rather than sprint crunch, --tier fast for most calls rather than quality-tier for everything.

Learning and mastery

Shu-ha-ri — 守破離 (しゅはり) — three stages of mastery from martial arts.

守 (まもる, obey) — learn the rules exactly as taught. Do not deviate. Understand the form before questioning it.

破 (やぶる, break) — having mastered the rules, examine why they exist. Begin to adapt. The deviation is informed, not ignorant.

離 (はなれる, leave) — transcend the rules entirely. Create new forms. The rules are internalized so deeply they no longer constrain.

Altshuller's 5 levels of invention map almost exactly to 守破離. The triz --tier system (fast/standard/quality) is a rough 守破離 proxy.

Hansei — 反省 (はんせい) — self-reflection before improvement. Mandatory acknowledgment of failure or shortcoming. In Toyota culture, hansei is not optional and not brief. Kaizen (改善, continuous improvement) cannot begin without genuine hansei. The sequence is hansei → kaizen, never the reverse.

Kaizen — 改善 (かいぜん) — continuous improvement. Small, daily, everyone's responsibility. Not a project with an end date — a permanent practice. The improvement never completes. Each kaizen creates the conditions for the next.

Philosophy

Monozukuri — ものづくり — the art and spirit of making things. Not just manufacturing (製造, せいぞう). Covers technique (技術), spirit (精神), and the craftsman's pride (職人気質, しょくにんきしつ). A shokunin (職人, craftsperson) does not ship work they are not proud of. The work carries the maker's name.

Ma — 間 (ま) — negative space. The meaningful pause between notes, the void between pillars, the silence in conversation. What is not there defines what is there. In TRIZ: empty matrix cells are 間. Altshuller left them empty deliberately — no known solution exists for those contradiction pairs. Filling the silence with a hallucinated answer violates 間.

Shokunin kishitsu — 職人気質 (しょくにんきしつ) — the craftsman's disposition. Pride that refuses to release work that falls short of one's own standard. Not perfectionism (which delays indefinitely) but craft integrity (which ships when the work is genuinely good). The corpus confirmed state is the shokunin's stamp. needs_validation is the work not yet ready to bear the maker's name.

Quick reference