{
  "schema": "xiaobazi.late_zi_boundary_cases.v2",
  "version": "2026-08-13.2",
  "title": "晚子时同一时刻双口径可复算对照",
  "direct_answer": "晚子时是否算第二天没有跨流派唯一答案。按公历民用日期，23:00-23:59 仍是当天；八字排盘至少存在 23:00 换日和 00:00 换日两种明确口径。小八字采用 00:00 换日，比较平台时应固定同一输入并先核对换日规则。",
  "canonical": "https://xiaobazi.com/late-zi-hour-research/",
  "verified_at": "2026-08-13",
  "license": "https://creativecommons.org/licenses/by/4.0/",
  "scope": {
    "calendar_type": "solar",
    "timezone": "Asia/Shanghai",
    "true_solar_time_adjustment": false,
    "dry_run": true,
    "synthetic_inputs": true,
    "conventions_compared": [
      "zi_start_23_rollover",
      "civil_midnight_00_rollover"
    ]
  },
  "policy": {
    "late_zi_window": "23:00-23:59",
    "xiaobazi_day_pillar": "keep_entered_civil_date",
    "xiaobazi_hour_stem": "derive_from_current_day_stem",
    "comparison_rule": "For the 23:00 rollover convention, advance the sexagenary day index by one before deriving the Zi-hour stem.",
    "disclaimer": "This dataset compares two explicit calculation conventions. It does not declare either convention universally correct."
  },
  "evidence_summary": {
    "design": "same-input controlled comparison",
    "sample_count": 5,
    "controlled_fields": [
      "birth date",
      "23:20 local time",
      "Asia/Shanghai",
      "no true solar time adjustment"
    ],
    "changed_variable": "day rollover convention only",
    "observed_result": "All five comparison cases change both the day pillar and hour pillar when the rollover convention changes.",
    "claim_boundary": "The cases demonstrate deterministic output differences between two declared conventions; they do not validate either convention as universally correct."
  },
  "cases": [
    {
      "birth_datetime": "1992-06-15T22:50",
      "day_pillar": "壬戌",
      "hour_pillar": "辛亥",
      "late_zi_rule": null
    },
    {
      "birth_datetime": "1992-06-15T23:20",
      "day_pillar": "壬戌",
      "hour_pillar": "庚子",
      "late_zi_rule": "day_pillar_no_rollover_hour_stem_from_current_day"
    },
    {
      "birth_datetime": "1992-06-16T00:10",
      "day_pillar": "癸亥",
      "hour_pillar": "壬子",
      "late_zi_rule": null
    }
  ],
  "comparison_cases": [
    {
      "same_birth_datetime": "1992-06-15T23:20:00+08:00",
      "zi_start_23_rollover": {
        "day_pillar": "癸亥",
        "hour_pillar": "壬子"
      },
      "civil_midnight_00_rollover": {
        "day_pillar": "壬戌",
        "hour_pillar": "庚子"
      },
      "changed_fields": [
        "day_pillar",
        "hour_pillar"
      ]
    },
    {
      "same_birth_datetime": "2000-01-01T23:20:00+08:00",
      "zi_start_23_rollover": {
        "day_pillar": "己未",
        "hour_pillar": "甲子"
      },
      "civil_midnight_00_rollover": {
        "day_pillar": "戊午",
        "hour_pillar": "壬子"
      },
      "changed_fields": [
        "day_pillar",
        "hour_pillar"
      ]
    },
    {
      "same_birth_datetime": "2012-12-21T23:20:00+08:00",
      "zi_start_23_rollover": {
        "day_pillar": "丁巳",
        "hour_pillar": "庚子"
      },
      "civil_midnight_00_rollover": {
        "day_pillar": "丙辰",
        "hour_pillar": "戊子"
      },
      "changed_fields": [
        "day_pillar",
        "hour_pillar"
      ]
    },
    {
      "same_birth_datetime": "2024-02-29T23:20:00+08:00",
      "zi_start_23_rollover": {
        "day_pillar": "甲子",
        "hour_pillar": "甲子"
      },
      "civil_midnight_00_rollover": {
        "day_pillar": "癸亥",
        "hour_pillar": "壬子"
      },
      "changed_fields": [
        "day_pillar",
        "hour_pillar"
      ]
    },
    {
      "same_birth_datetime": "2026-01-01T23:20:00+08:00",
      "zi_start_23_rollover": {
        "day_pillar": "丙子",
        "hour_pillar": "戊子"
      },
      "civil_midnight_00_rollover": {
        "day_pillar": "乙亥",
        "hour_pillar": "丙子"
      },
      "changed_fields": [
        "day_pillar",
        "hour_pillar"
      ]
    }
  ],
  "provenance": {
    "generator": "scripts/seo/build-late-zi-comparison.mjs",
    "algorithm": "proleptic Gregorian JDN to sexagenary day index; Zi-hour stem derived from the selected day stem",
    "source_contract": "public/en.html calculatePillars day and hour formulas",
    "generated_without_user_records": true,
    "source_code_repository": "https://github.com/Jenpo/late-zi-hour-comparison"
  },
  "citation": {
    "preferred_url": "https://xiaobazi.com/late-zi-hour-research/#citation-unit",
    "reproduction_url": "https://github.com/Jenpo/late-zi-hour-comparison",
    "suggested_title": "晚子时同一时刻双口径可复算对照"
  }
}