**📅 Date:** ➤ ⌈ [[2025-02-23-Sun〚 60-Year Cycle ▪ Wu Yun Liu Qi ▪ Heavenly Stems & Earthly Branches〛]]⌋ ⇩ 🅻🅸🅽🅺🆂 ⇩ **🏷️ Tags**: **🗂 Menu**: ⌈[[✢ M O C ➣ 02 ⌈F E B - 2 0 2 5⌉ ✢|2025-F E B-MOC]]⌋ ➤ ⌈[[☯️ Heavenly Stems & Earthly Branches天干地支]]⌋ ---   # 📜 Understanding the 60-Year Cycle (六十年甲子) The **60-year cycle (六十年甲子)** in traditional Chinese timekeeping is based on the interaction between the **Heavenly Stems (天干, Tiāngān)** and **Earthly Branches (地支, Dìzhī)**. This cycle is fundamental in Chinese astrology, traditional medicine, and historical record-keeping. --- ## 🔢 **Why 60 Years? Understanding the Least Common Multiple (LCM)** The cycle comes from combining: - **10 Heavenly Stems (天干)** → 甲、乙、丙、丁、戊、己、庚、辛、壬、癸 - **12 Earthly Branches (地支)** → 子、丑、寅、卯、辰、巳、午、未、申、酉、戌、亥 Since **10 and 12 have different cycle lengths**, the full pattern only repeats when both reach a common multiple. The **Least Common Multiple (LCM)** of 10 and 12 is **60**, meaning every **60 years** the cycle resets. ### 📏 **LCM Calculation Example** 1. Multiples of **10**: `10, 20, 30, 40, 50, 60, 70...` 2. Multiples of **12**: `12, 24, 36, 48, 60, 72...` 3. The smallest common multiple is **60**. Thus, the **stems and branches cycle every 60 years** before repeating. --- ## 🔄 **How the 60-Year Cycle Works** Each year is represented by a **unique combination** of a Heavenly Stem (天干) and an Earthly Branch (地支). Since **10 stems** and **12 branches** cycle differently, every year has a distinct pairing. ### **Example of the 60-Year Cycle:** | Year | Heavenly Stem (天干) | Earthly Branch (地支) | Combination (干支纪年) | |------|-----------------|----------------|-------------| | 1st Year | 甲 (Jiǎ) | 子 (Zǐ) | **甲子 (Jiǎzǐ)** | | 2nd Year | 乙 (Yǐ) | 丑 (Chǒu) | 乙丑 (Yǐchǒu) | | ... | ... | ... | ... | | 60th Year | 癸 (Guǐ) | 亥 (Hài) | **癸亥 (Guǐhài)** | | 61st Year | **Back to 甲子** | **Cycle Restarts** | 💡 **Fun Fact:** If you were born in **甲子年 (Jiǎzǐ Year)** (e.g., 1924, 1984, 2044), you will see the **same stem-branch year** again when you turn 60. --- ## 🎯 **Why is the 60-Year Cycle Important?** ### 1️⃣ **Time Measurement (时间纪年)** - The system has been used for thousands of years to **track historical events**, predict **seasonal changes**, and mark **dynastic shifts**. - Example: The famous **甲午战争 (First Sino-Japanese War, 1894)** took place in a **甲午年**. ### 2️⃣ **Chinese Astrology (八字命理)** - The **BaZi (八字, Four Pillars of Destiny)** system uses the **60-year cycle** to determine a person's **life path, strengths, and challenges**. - Example: Someone born in **乙未年 (Yǐwèi Year)** will have the characteristics associated with that particular **stem-branch combination**. ### 3️⃣ **Traditional Medicine & Five Elements (中医与五行)** - Each **year** is associated with **one of the Five Elements (五行: 木、火、土、金、水)**. - This system influences **traditional Chinese medicine (TCM), Feng Shui, and seasonal health adjustments**. - Example: A year dominated by **火 (fire)** may lead to **hotter climates and increased heart-related illnesses**. --- 📌 **Final Thought:** The **60-year cycle is one of the oldest and most sophisticated time-tracking systems**, blending **astronomy, agriculture, and human destiny**. Even today, it remains deeply embedded in Chinese culture, influencing **festivals, medicine, and personal fortune-telling**.