diff --git a/docs/BUG_HISTORY.md b/docs/BUG_HISTORY.md
index 5c16165a..d35bd2b4 100644
--- a/docs/BUG_HISTORY.md
+++ b/docs/BUG_HISTORY.md
@@ -21240,3 +21240,20 @@
 - 关联记录：BUG-1541、BUG-1220（年盘保留秒）。
 - 复发自：无
 - 修复版本：分支 `codex/upstream-skill-sync-20261104`，待合并。
+
+## BUG-1543 | KP 子主星与宫头用的是显示用的四舍五入值
+
+- 状态：resolved（代码 + 回归测试；待部署）
+- 首次发现 / 最近更新：2026-11-04（上游同步第十轮核对上游 `26d5a52d`）/ 2026-11-04
+- 影响面：`scripts/jyotish_engine.py` `cmd_kp`（命令 `kp`、`/api/kp` 一类入口）。KP 在商业覆盖层仍是 `reference_only`。
+- 现象：行星落在星主 / 子主 / 子子主分界附近、或宫头附近时，KP 表可能差一格。
+- 触发条件：行星度数或宫头离 KP 分界小于约 0.0001 度；出生时间带秒。
+- 根因：`cmd_kp` 把 `calculate_bhava_boundaries()` 返回的宫头（保留 4 位小数）、行星的 `degree_in_sign`（保留 4 位小数）和星盘结果里的 `julian_day`（保留 6 位小数，约 0.09 秒）交给 KP 分析，KP 分界是按原始经度切的。上游同一缺陷，10-16 修复，第九轮没核对。
+- 修复：按出生时刻重算儒略日（与 `compute_chart_data` 同一公式，含秒）；宫头改用 `calculate_cusps()` 原值；行星度数用 `degree_raw % 30`，没有原值时才退回显示值。
+- 验证：新测试 `tests/test_upstream_sync10_kp_unrounded_inputs.py`（移植上游 `tests/test_kp_unrounded_inputs.py`）：儒略日、宫头、行星度数都是原值；改前失败、改后通过。`test_kp_system.py`、`test_kp_cusp_house_assignment.py`、`test_kp_monthly_report_packet.py` 5 条通过、2 条跳过；公开名人盘实跑 `cmd_kp` 正常返回。
+- 影响输出：只有贴着分界的行星或宫头会换一格，其余逐字节相同。不涉及冻结身份文件。
+- 未搬：同一上游提交里的 Vivaha Saham 昼夜公式与 Yoga 燃烧状态透传，见本轮进度记录。
+- 防复发：上述测试；显示用的取整值不进计算。
+- 关联记录：BUG-1383（KP 边界，第八轮）、BUG-1541、BUG-1542。
+- 复发自：无
+- 修复版本：分支 `codex/upstream-skill-sync-20261104`，待合并。
diff --git a/scripts/jyotish_engine.py b/scripts/jyotish_engine.py
index ecd9b65b..bfbe45a5 100644
--- a/scripts/jyotish_engine.py
+++ b/scripts/jyotish_engine.py
@@ -13749,6 +13749,12 @@ def cmd_kp(args):
         _apply_ayanamsa(requested_report_ayanamsa)
         return {"error": "swisseph未安装"}
 
+    # The chart's julian_day is rounded for display. KP cusp and sub-lord
+    # boundaries use the civil instant itself, seconds included (upstream
+    # 26d5a52d, BUG-1543). Same formula as compute_chart_data.
+    jd = swe.julday(args.year, args.month, args.day,
+                    _birth_hour_decimal(args.hour, args.minute, _arg_second(args)) - args.tz)
+
     asc_sign = chart.get("ascendant", {}).get("sign", "Aries")
     planets = chart.get("planets", {})
     planet_lons = {
@@ -13762,7 +13768,8 @@ def cmd_kp(args):
     from bhava_chalit import BhavaChalitCalculator
     kp_house_calculator = BhavaChalitCalculator()
     asc_lon = chart.get('ascendant', {}).get('degree_raw', chart.get('ascendant', {}).get('degree', 0.0))
-    boundaries = kp_house_calculator.calculate_bhava_boundaries(
+    # Unrounded cusps; calculate_bhava_boundaries rounds them to 4 decimals.
+    raw_cusps = kp_house_calculator.calculate_cusps(
         float(asc_lon), 0.0, 'placidus', jd, args.lat, args.lon,
     )
     bhava_chart = kp_house_calculator.get_bhava_chalit_chart(
@@ -13776,16 +13783,19 @@ def cmd_kp(args):
     for pname, pdata in planets.items():
         if isinstance(pdata, dict) and 'sign' in pdata:
             bhava_row = bhava_planets.get(pname) if isinstance(bhava_planets.get(pname), dict) else {}
+            raw_lon = planet_lons.get(pname)
             planet_positions[pname] = {
                 'sign': pdata['sign'],
-                'degree': pdata.get('degree_in_sign', pdata.get('degree', 0) % 30),
+                # degree_in_sign is rounded to 4 decimals for display.
+                'degree': (float(raw_lon) % 30 if raw_lon is not None
+                           else pdata.get('degree_in_sign', pdata.get('degree', 0) % 30)),
                 'house': bhava_row.get('bhava_house', pdata.get('house', 1)),
             }
 
     result = calc_kp_analysis(
         planet_positions,
         asc_sign,
-        house_cusps=boundaries.get('cusps'),
+        house_cusps=raw_cusps,
         house_occupancy_basis='cusp_to_cusp',
     )
     moon_lon = planets.get('Moon', {}).get('degree_raw', planets.get('Moon', {}).get('degree', 0.0)) if isinstance(planets.get('Moon'), dict) else 0.0
diff --git a/tests/test_upstream_sync10_kp_unrounded_inputs.py b/tests/test_upstream_sync10_kp_unrounded_inputs.py
new file mode 100644
index 00000000..9db80a38
--- /dev/null
+++ b/tests/test_upstream_sync10_kp_unrounded_inputs.py
@@ -0,0 +1,48 @@
+"""KP must not reuse display-rounded time, cusps or planet degrees (BUG-1543).
+
+Ported from upstream yinduzhanxing 26d5a52d tests/test_kp_unrounded_inputs.py
+(sync 10). Synthetic chart only.
+"""
+import sys
+from pathlib import Path
+from types import SimpleNamespace
+
+ROOT = Path(__file__).resolve().parents[1]
+sys.path.insert(0, str(ROOT / 'scripts'))
+import jyotish_engine as engine  # noqa: E402
+from bhava_chalit import BhavaChalitCalculator  # noqa: E402
+
+
+def test_kp_passes_raw_time_cusps_and_longitudes(monkeypatch):
+    args = SimpleNamespace(year=2000, month=1, day=2, hour=3, minute=4, second=5,
+                           lat=20., lon=75., tz=5.5, ayanamsa='raman')
+    chart = {'ascendant': {'sign': 'Aries', 'degree_raw': 12.123456789},
+             'planets': {'Sun': {'sign': 'Aries', 'degree_raw': 1.234567891, 'degree_in_sign': 1.2346},
+                         'Moon': {'sign': 'Taurus', 'degree_raw': 42.987654321, 'degree_in_sign': 12.9877}}}
+    raw_cusps = [12.123456789 + 30 * i for i in range(12)]
+    seen = {}
+    monkeypatch.setattr(engine, '_compute_chart_from_args', lambda a: (chart, 0, 2451545., 23.))
+
+    def cusps(self, asc, mc, hs, jd, lat, lon):
+        seen['jd'] = jd
+        return raw_cusps
+
+    monkeypatch.setattr(BhavaChalitCalculator, 'calculate_cusps', cusps)
+    monkeypatch.setattr(BhavaChalitCalculator, 'get_bhava_chalit_chart',
+                        lambda *a, **k: {'planets': {'Sun': {'bhava_house': 12}, 'Moon': {'bhava_house': 2}}})
+
+    def analyze(planets, asc, **kwargs):
+        seen['planets'] = planets
+        seen.update(kwargs)
+        return {}
+
+    monkeypatch.setattr(engine, 'calc_kp_analysis', analyze)
+    monkeypatch.setattr(engine, 'attach_calculation_profile', lambda result, args: result)
+    monkeypatch.setattr(engine, '_build_response_envelope', lambda command, result, **k: result)
+    engine.cmd_kp(args)
+    expected = engine.swe.julday(2000, 1, 2, 3 + 4 / 60 + 5 / 3600 - 5.5)
+    assert seen['jd'] == expected and seen['jd'] != round(expected, 6)
+    assert seen['house_cusps'] == raw_cusps
+    assert seen['planets']['Sun']['degree'] == 1.234567891
+    assert seen['planets']['Moon']['degree'] == 42.987654321 % 30
+    assert seen['house_occupancy_basis'] == 'cusp_to_cusp'