<p>Debates on end-of-life decision-making in Japan have often centered on treatment limitation—particularly the withholding and contested withdrawal of life-sustaining treatment—and on questions of permissibility, autonomy, and legal safeguards. While ethically important, this focus has tended to privilege rare and highly visible decision moments, leaving comparatively underexamined the everyday structuring of care that shapes treatment trajectories for far larger numbers of patients. This article introduces quiet large-scale triage (QLT) as a diagnostic framework for understanding how end-of-life trajectories are shaped within the institutional and practice-based structuring of care. Under QLT, options are filtered outside explicit deliberation—often before they become candidates for consent or refusal—through referral thresholds, resource constraints, care pathways, and routinized expectations. Here, “quiet” denotes ethical invisibility rather than intentional concealment, capturing how cumulative constraints limit feasible options without becoming recognizable as ethical decisions. The framework also clarifies how autonomy-supporting practices, such as advance care planning and do-not-resuscitate decisions, may become normatively entangled with institutional and practice-based constraints. Rather than adjudicating the permissibility of life-ending interventions, this perspective redirects ethical inquiry toward where accountability should lie when the structuring of care shapes options prior to explicit deliberation. By foregrounding routine allocation effects, the article provides a concise basis for ethical reflection on explanation, reviewability, and institutional responsibility in end-of-life care.</p>