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REFORMED HIJRI CALENDAR (LUNISOLAR) Operational Charter
Preamble. This calendar preserves twelve named lunar months in fixed order, the four sacred months by permanent identity, and the original seasonal anchors of Ramadan in summer and Hajj in autumn. Seasonal anchor is maintained by a deterministic nineteen-year intercalation rule. The calendar governs sacred observances. Civil affairs operate on a parallel solar calendar.
I. Month Structure. The year consists of twelve lunar months in fixed order: Muharram, Safar, Rabi al-Awwal, Rabi al-Akhir, Jumada al-Awwal, Jumada al-Akhirah, Rajab, Sha'ban, Ramadan, Shawwal, Dhul-Qa'dah, Dhul-Hijjah. Each month begins at the astronomical new moon and contains twenty-nine or thirty days. Total length of a normal year: three hundred fifty-four or three hundred fifty-five days.
II. Sacred Months. Four months retain sacred status with identity fixed permanently: Muharram (month one), Rajab (month seven), Dhul-Qa'dah (month eleven), Dhul-Hijjah (month twelve). Sacred status cannot be shifted, transferred, suspended, or reassigned under any circumstance. Three sacred months are in succession (Dhul-Qa'dah, Dhul-Hijjah, Muharram) per the Farewell Sermon enumeration. Rajab stands separately at month seven.
III. Seasonal Anchors. Ramadan (month nine) is anchored to summer, June through August in the Northern Hemisphere. Hajj on 10 Dhul-Hijjah is anchored to the autumn equinox window, mid-September through late October. Ashura on 10 Muharram falls in late autumn. Rajab falls in spring. The anchors are maintained by fixed intercalation rule, not by discretion.
IV. Intercalation Rule. A nineteen-year Metonic cycle governs intercalation. In each cycle, seven years carry an intercalary month: years three, six, eight, eleven, fourteen, seventeen, and nineteen of the cycle. The intercalary month is named Sha'ban Thaniya (Second Sha'ban) and is inserted between Sha'ban (month eight) and Ramadan (month nine). The intercalary month carries thirty days. Sha'ban Thaniya is non-sacred and serves only the function of preserving seasonal anchor. No other intercalation is permitted.
V. Cycle Arithmetic. Across one nineteen-year cycle, twelve normal years and seven leap years yield six thousand nine hundred thirty-nine to six thousand nine hundred forty days, matching nineteen tropical solar years (approximately 6,939.6 days) within two hours. Ramadan remains within the summer window and Hajj remains within the autumn equinox window across all years of the cycle.
VI. Long-Term Correction. Residual drift accumulates at approximately five days per millennium. To correct this, one intercalary month is omitted from a designated leap year approximately every fourteen hundred years by broad scholarly and astronomical consensus across multiple jurisdictions. This correction is rare, transparent, pre-announced, and beyond the authority of any single ruler, state, or council acting alone.
VII. Prohibited Practices. Sacred-month identity reassignment for any reason is forbidden. Year-by-year discretionary adjustment of intercalation is forbidden. Adjustment of intercalation timing to favor warfare, trade, taxation, tourism, or political advantage is forbidden. Renaming, demoting, or promoting any month is forbidden. Any form of the corruption mechanism named in Quran 9:37 is forbidden.
VIII. Permitted and Required Practices. The intercalation cycle is public, mathematically deterministic, and immune to political tampering. Astronomical observation and computation determine new moon timing and seasonal alignment. Scholarly oversight monitors drift across centuries and proposes long-term corrections only by broad consensus. The calendar is published in advance for all years of each cycle.
IX. Dual Calendar Operation. This calendar governs sacred observances and religious commemorations exclusively. Civil affairs (taxation, contracts, banking, governance, vital records) operate on a separate solar civil calendar, typically Gregorian by jurisdiction. The two calendars run in parallel without conflict, following the ancient Hebrew dual-calendar precedent (religious year from Nisan, civil year from Tishrei) and the Babylonian and Egyptian dual-system traditions. Religious documents reference the sacred calendar. Commercial and civil documents reference the civil calendar. Both may be displayed together.
X. Transition Mechanism. Implementation begins at the future year when 10 Dhul-Hijjah on the current lunar Hijri calculation falls naturally within the autumn equinox window of mid-September to late October. From that year forward, the nineteen-year cycle begins at year one. No discretionary one-time bulk correction is applied. The transition is achieved by selecting the start year, not by adjusting any year's internal content. This avoids any procedure resembling Nasi' adjudication.
XI. Reference Layout (Normal Year). Muharram falls in October to November. Safar in November to December. Rabi al-Awwal in December to January. Rabi al-Akhir in January to February. Jumada al-Awwal in February to March. Jumada al-Akhirah in March to April. Rajab in April to May. Sha'ban in May to June. Ramadan in June to July. Shawwal in July to August. Dhul-Qa'dah in August to September. Dhul-Hijjah in September to October. In leap years, all months from Ramadan onward shift forward by approximately thirty days but remain within their respective seasonal windows.
XII. Quranic and Hadith Foundation. Twelve months per year, preserved per Quran 9:36. Four sacred months by identity, preserved per Quran 9:36 and the Farewell Sermon enumeration. Prohibition on the Nasi' corruption mechanism (sacred-month identity shifting for warfare and trade), preserved per Quran 9:37. Lunar crescents as time measurement, preserved per Quran 2:189. The seasonal anchor of Ramadan and Hajj honors the geometric principle that commemorative events preserve the season-coordinate of the original events they commemorate, which underlies the cross-tradition Abrahamic festival pattern (Passover spring, Sukkot autumn, Akedah autumn, Yom Kippur autumn).
XIII. Authority. This calendar derives operational authority from the Quranic text directly, the Farewell Sermon directly, and the geometric principle of commemoration-coordinate-preservation that is empirically observable across all ancient Semitic, Indo-European, Sinitic, and Iranic sacred-time traditions.
End of Charter.