five-whys

Use for incident/bug root-cause analysis, postmortem, recurring-problem diagnosis, or process improvement. Triggers on Chinese phrases 复盘 / 根因 / postmortem / 又坏了 / 老是 / 重复出现 / 这不是第一次 / 为啥总是 / RCA, and English signals "this keeps happening", "RCA", "post-mortem", "incident review". Ask "why?" 3-7 times (5 is average not rule) until hit a process/system/design root that can be changed — not the symptom. Do NOT use for…