Six Star Astrology Calculator: How to Find Your Star Type (Seimeisu) From Your Birth Date

Six Star Astrology (Rokusei Senjutsu) does not care about your rising sign, and it certainly does not care what time you were born. Invented by Kazuko Hosoki in the 1980s, Japan’s fiercest divination system is a fatalistic, mathematically uncompromising engine. During its peak in the 1990s and 2000s, Hosoki wielded this system on national television to tell celebrities their marriages would fail and their careers were doomed. It categorizes humanity into six planetary archetypes—Saturn, Venus, Mars, Uranus, Jupiter, and Mercury—and dictates a rigid 12-year cycle of fortune and catastrophe. If you want a Six Star Astrology overview, the short version is this: it is a temporal map designed to tell you exactly when to launch a business, when to get married, and when to absolutely lay low and do nothing.

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But before you can read your fortune, you have to do the math to calculate your exact planetary archetype. Western astrology has trained us to plug our birth data into a black-box widget and accept whatever the server spits out. Doing the Six Star calculation by hand proves that the mathematics of destiny are grounded in the ancient Chinese sexagenary cycle. It is pure arithmetic. Here is the exact, step-by-step method to calculate your destiny number (seimeisu) and find your star type.

Step 1: Locate Your Base Destiny Number

The engine of Rokusei Senjutsu is a 60-base cycle, inherited directly from the ancient Chinese calendar system known as the Four Pillars of Destiny. Because the modern Gregorian calendar does not align neatly with the ancient Chinese lunar and solar calendars, finding your starting point requires a reference table. This table gives you your "Base Number" (運命数) depending on the exact year and month you were born. It acts as the mathematical offset to sync your birth month with the 60-day repeating sequence.

Below is a skimmable birth-year reference table for the early 1990s to demonstrate the lookup process. If you were born outside these specific years, you will use the exact same mechanical process with a full 100-year ephemeris (readily available in any Rokusei Senjutsu almanac).

Find your birth year and month. For example, if you were born in August 1991, your Base Number is 32. Write this number down.

Step 2: The Core Calculation

Once you have your Base Number, the actual arithmetic begins. You need to calculate your Star Number (星数), which will permanently lock you into one of the six planetary types.

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The formula for the arithmetic of destiny is rigid and immutable. You start with the base number, then subtract 1, and finally add birth day. Why the base number minus 1? In traditional East Asian timekeeping, the concept of a "zero" year or "zero" day does not exist. The day you are born counts as your first day of life, so the math adjusts for an inclusive count to prevent you from skipping forward in the cycle.

If your final result is greater than the maximum value 60, you must execute a sexagenary cycle reset. Simply put: if over 60, subtract 60. The cycle resets every two months, so there is no such thing as a final star number of 61 or 75. If you hit 61, you are back at 1.

Step 3: Map to Your Star Type

Your calculated Star Number (1 through 60) maps directly to one of the six destiny stars (星人). These are the core archetypes of the 60-day cycle. They are not astronomical planets; they are symbolic brackets representing your fundamental personality and life path.

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Here is how the numbers break down and what they mean for your personality:

• 1 to 10: Saturn (土星人) – The idealistic perfectionist. Ruled by logic and an unyielding sense of justice, they struggle with emotional expression but excel in solitary, highly focused pursuits. They are the architects of the zodiac, building systems that last, but they often alienate those who cannot meet their impossible standards.
• 11 to 20: Venus (金星人) – The trendsetting free spirit. Highly social and deeply restless, they thrive on action and completely despise stagnation. They live entirely in the present tense. A Venus type is the life of the party, but their aversion to long-term planning can leave them vulnerable during hard times.
• 21 to 30: Mars (火星人) – The eccentric mystic. Deeply intuitive and prone to living in their own heads, they are fiercely independent but often socially awkward. Mars types possess a natural radar for reading rooms, but they prefer to observe from the fringes rather than lead the charge.
• 31 to 40: Uranus (天王星人) – The stubborn pragmatist. Family-oriented, emotional, and intensely loyal. They operate on gut feeling rather than cold logic. They are the ultimate caregivers, but their refusal to compromise on their core values can make them incredibly frustrating in a professional setting.
• 41 to 50: Jupiter (木星人) – The stoic traditionalist. Cautious, methodical, and incredibly slow to anger. They build wealth and relationships over decades, not days. A Jupiter type will rarely take a bold risk, preferring the safety of a guaranteed, albeit slow, return on investment.
• 51 to 60: Mercury (水星人) – The charismatic opportunist. Brilliant networkers and financially driven, but emotionally detached. They rule the material world and rarely let sentiment cloud their judgment. If a Mercury type is in your corner, you will likely make money, but do not expect a shoulder to cry on.

Step 4: Determine Your Polarity (+/-)

In Six Star Astrology, every star type is split into a Plus (+) or Minus (-) polarity. This polarity determines whether you follow the standard 12-year timing track or an inverted one, which is vital for calculating your personal Daisakkai (the three-year period of bad luck). It is determined by the Zodiac animal of your birth year.

Annotated Diagram: Polarity and Chinese Zodiac yearsauto_awesomeGenerate one like thisarrow_forward

The rule is straightforward and mirrors the Yin and Yang of traditional Chinese cosmology:

• Plus (+) Polarity includes Rat, Tiger, Dragon, Horse, Monkey, Dog. These are traditionally the Yang (odd-numbered) years in the Chinese cycle, associated with outward energy and active momentum.
• Minus (-) Polarity includes Ox, Rabbit, Snake, Sheep, Rooster, Pig. These are the Yin (even-numbered) years, associated with inward reflection, preservation, and passive strength.

However, there is a massive trap for early-year babies. The cycle resets at Risshun in early February (usually February 3rd or 4th), not on January 1st. This means January births must use the previous year. If you were born on January 15, 1991, you belong to the 1990 Zodiac year (Horse, Plus), not the 1991 year (Sheep, Minus). Failing to account for Risshun will completely invalidate your chart.

Worked Examples: The Engine in Motion

Let’s run the formula on a few specific birth dates to see the engine in motion and prove how simple it actually is.

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Example A: November 20, 1990

1. Lookup: Looking at the 1990 row in our table, the Base Number is 59.
2. Calculation: We plug it into the formula: (59 - 1) + 20 = 78.
3. Modulo Rule: Since 78 is greater than 60, we subtract 60. The Star Number is 18.
4. Star Type: 18 falls in the 11–20 bracket. This person is a Venus type.
5. Polarity: 1990 is the Year of the Horse. The Horse is a Plus (+) year. Result: Venus (+) confirmed.

Example B: February 14, 1992

1. Lookup: Looking at the 1992 row, February is 36.
2. Calculation: (36 - 1) + 14 = 49.
3. Modulo Rule: 49 is under 60. The Star Number is 49.
4. Star Type: 49 falls in the 41–50 bracket. This person is a Jupiter type.
5. Polarity: 1992 is the Year of the Monkey. The Monkey is a Plus (+) year. (Since February 14 is comfortably after Risshun, they safely use 1992). Result: Jupiter (+).

Example C: July 4, 1991

1. Lookup: In the 1991 row, July is 1.
2. Calculation: (1 - 1) + 4 = 4.
3. Modulo Rule: 4 is under 60. The Star Number is 4.
4. Star Type: 4 falls in the 1–10 bracket. This person is a Saturn type.
5. Polarity: 1991 is the Year of the Sheep. The Sheep is a Minus (-) year. Result: Saturn (-).

Once you have your exact planetary type and polarity, the black box is officially open. You are no longer guessing at your archetype; you have mathematically proven your place in the sexagenary cycle. Your next step is applying this to the temporal map. You can look up your 2026 horoscope by type to see what phase of the 12-year cycle you are currently enduring, or check if you're in your Daisakkai—the dreaded three-year winter where major life decisions are strictly forbidden. The math is done. The destiny is set. Proceed with caution.

Sources

• Hosoki, Kazuko. Rokusei Senjutsu Tells Your Fortune.
• Standard Bazi (Four Pillars of Destiny) sexagenary day-pillar calculations.
• Japanese astrological ephemeris data for the Heisei era (1990–1992).