Lunar and Solar Calendar: Introduction to Chinese Traditional Calendar

## Introduction to Chinese Calendar

China uses two calendars simultaneously:
- **Solar Calendar (Gregorian)**: Internationally used solar calendar based on Earth's revolution around the sun
- **Lunar Calendar**: Traditional Chinese calendar based on moon phases while considering solar position

## Basic Concepts of Lunar Calendar

### Month Settings
- Lunar year has 12 months, each 29 or 30 days
- Based on synodic month (moon phase cycle), about 29.53 days
- Big months have 30 days, small months have 29 days

### Leap Months
To coordinate the lunar calendar with seasons, a leap month system is used:
- Add one leap month every 2-3 years
- Leap month repeats the previous month's name, like "Leap April"
- Years with leap months have 13 months

### 24 Solar Terms
The lunar calendar divides the year into 24 solar terms reflecting sun position:
- **Spring**: Beginning of Spring, Rain Water, Awakening of Insects, Spring Equinox, Pure Brightness, Grain Rain
- **Summer**: Beginning of Summer, Grain Full, Grain in Ear, Summer Solstice, Minor Heat, Major Heat
- **Autumn**: Beginning of Autumn, Limit of Heat, White Dew, Autumn Equinox, Cold Dew, Frost's Descent
- **Winter**: Beginning of Winter, Minor Snow, Major Snow, Winter Solstice, Minor Cold, Major Cold

## Gan-Zhi Year System

### Ten Heavenly Stems
Jia, Yi, Bing, Ding, Wu, Ji, Geng, Xin, Ren, Gui

### Twelve Earthly Branches
Zi, Chou, Yin, Mao, Chen, Si, Wu, Wei, Shen, You, Xu, Hai

### Combination Pattern
Heavenly stems and earthly branches pair in sequence, forming a 60-year cycle:
- Jiazi, Yichou, Bingyin...Guihai
- 2024 is Jiachen year
- 2025 is Yisi year

## Chinese Zodiac

Twelve earthly branches correspond to twelve animals:
| Branch | Zodiac | Example Years |
|--------|--------|---------------|
| Zi | Rat | 2020, 2032 |
| Chou | Ox | 2021, 2033 |
| Yin | Tiger | 2022, 2034 |
| Mao | Rabbit | 2023, 2035 |
| Chen | Dragon | 2024, 2036 |
| Si | Snake | 2025, 2037 |
| Wu | Horse | 2026, 2038 |
| Wei | Goat | 2027, 2039 |
| Shen | Monkey | 2028, 2040 |
| You | Rooster | 2029, 2041 |
| Xu | Dog | 2030, 2042 |
| Hai | Pig | 2031, 2043 |

## Important Lunar Festivals

| Festival | Lunar Date | Solar Date (2024) |
|----------|------------|-------------------|
| Spring Festival | 1st day of 1st month | Feb 10 |
| Lantern Festival | 15th day of 1st month | Feb 24 |
| Dragon Boat Festival | 5th day of 5th month | Jun 10 |
| Qixi Festival | 7th day of 7th month | Aug 10 |
| Mid-Autumn Festival | 15th day of 8th month | Sep 17 |
| Double Ninth Festival | 9th day of 9th month | Oct 11 |

## Applications of Lunar Calendar Conversion

### Birthday Conversion
Many people celebrate lunar birthdays:
- Solar May 15, 1990
- Lunar April 21, Gengwu year

### Auspicious Day Selection
Traditionally, weddings, moves, and important events choose auspicious days:
- Reference the almanac
- Avoid clashes
- Choose auspicious hours

### Agricultural Planting
24 solar terms guide agricultural production:
- Around Pure Brightness, plant melons and beans
- During Grain in Ear, plant busily

## Using Lunar Calendar Converter

Our lunar calendar converter supports:
- Bidirectional conversion between solar and lunar
- Display Gan-Zhi year and zodiac
- Date range 1900-2100
- Solar term information

## FAQ

**Q: Why does Lunar New Year fall on different dates each year?**
A: The lunar calendar is based on moon phases, with about 354 days per year, 11 days fewer than the solar calendar, so Lunar New Year varies in the solar calendar.

**Q: How to celebrate birthdays in leap months?**
A: Traditionally celebrate in the previous month, or choose the solar birthday.

**Q: How to quickly know the zodiac of a year?**
A: Divide the year by 12, determine by remainder: 4-Rat, 5-Ox, 6-Tiger, 7-Rabbit, 8-Dragon, 9-Snake, 10-Horse, 11-Goat, 0-Monkey, 1-Rooster, 2-Dog, 3-Pig.