Astrology on the internet is mostly a black box. You plug your birth date into a widget, hit submit, and a server spits out your destiny. For millions of people discovering Kazuko Hosoki’s Six-Star Astrology (Rokusei Senjutsu)—especially following the global success of Netflix’s Straight to Hell—the impulse is exactly the same. Find a calculator, get your type, and move on to the horoscope.
But relying on a black box strips away the mechanical beauty of the system. Western astrology has trained us to view divination as a soft, interpretive art—a psychological tool where every challenging placement is just a "growth opportunity." Six-Star Astrology does not care about your personal growth. Hosoki built a highly rigid, mathematically consistent framework derived from the ancient Chinese sexagenary cycle. It is fatalistic, precise, and entirely unconcerned with your feelings.
Doing the math by hand proves that the system is doing real arithmetic, not just serving up algorithmic vibes. It grounds the mysticism in undeniable logic. If you want to know your star type right now, you are going to learn how to calculate it yourself. We are going to walk through the exact formula—heavenly stem, earthly branch, and polarity—using a real birth date. Once you understand the engine, you can use the automated calculators for everyone else.
What You Actually Need (And What You Don’t)
To calculate your Six-Star type, you only need three pieces of information: your birth year, your birth month, and your birth day.
Unlike Western astrology, which demands your exact time of birth down to the minute and the precise geographic coordinates of the hospital where you were born, Six-Star Astrology is strictly calendar-based. It does not care about the ascendant rising over the horizon or the specific degree of the moon in your twelfth house. It is an arithmetic derivation of the traditional East Asian lunisolar calendar, mapped onto the Gregorian calendar for modern convenience.
Why does time not matter? Because the sexagenary cycle (the 60-term cycle of stems and branches) operates on whole days. You are assigned the energy of the specific day you entered the world's grid. This makes the system incredibly accessible, but also unforgiving. There are no cusps. There is no "moon in Venus" nuance to soften the blow. You belong to one of six planetary bases, and you carry a Positive (Plus) or Negative (Minus) polarity. That is your fixed temperament for life, and it dictates exactly where you stand in the inescapable twelve-year cycle of fortune and ruin.
The Step-by-Step Calculation (With a Worked Example)
The formula to find your star requires a bit of mathematical legwork. We will use a random, standard birth date for our worked example: November 20, 1975.
Step 1: Find Your Destiny Number (Unmei-su) The foundation of the calculation is your Destiny Number. This is a base value assigned to your specific birth year and birth month, derived from standardized sexagenary tables. Because the full century-long lookup table is massive, practitioners historically relied on Hosoki’s printed almanacs to find this starting integer. Today, you can find these tables archived across Japanese astrology sites.
For our example (November 1975), the lookup table gives us a Destiny Number of 48.
Step 2: Calculate Your Star Number (Hoshi-su) Here is where the actual math happens. The formula is beautifully simple: (Destiny Number - 1) + Birth Day = Star Number
Let’s plug in our example's numbers: Destiny Number: 48 Minus 1: 47 Add Birth Day (20): 47 + 20 = 67
The Rule of 60: Because the system is built on a 60-step cycle, your Star Number can never exceed 60. If your final sum is 61 or higher, you simply subtract 60. If your sum is 60 or below, you leave it exactly as it is.
Our result is 67. Since 67 is greater than 60, we subtract 60. 67 - 60 = 7. Our final Star Number is 7.
Step 3: Determine Your Star Base Your Star Number corresponds directly to one of the six celestial archetypes.
- 1 to 10: Saturn (土星)
- 11 to 20: Venus (金星)
- 21 to 30: Mars (火星)
- 31 to 40: Uranus (天王星)
- 41 to 50: Jupiter (木星)
- 51 to 60: Mercury (水星)
Our Star Number is 7, which falls in the 1–10 bracket. Therefore, the base star is Saturn.
Step 4: Determine Your Polarity (Plus or Minus) Finally, you need your polarity. This is determined entirely by the Chinese zodiac animal of your birth year. Odd-numbered years in the zodiac cycle are Positive (+), and even-numbered years are Negative (-).
- Positive (+): Rat, Tiger, Dragon, Horse, Monkey, Dog
- Negative (-): Ox, Rabbit, Snake, Sheep, Rooster, Pig
Our subject was born in 1975, which is the Year of the Rabbit. The Rabbit is a Negative (-) year. Combine the base and the polarity, and our final result is Saturn Minus.
If you are putting together a personal birth chart presentation, a digital grimoire, or just a mood board for your new astrological identity, visual aesthetics matter. You can use BgRemovit’s AI photo generation to create striking, customized avatars based on your specific planetary archetype—like a stoic, earth-toned portrait for a Saturn type, or a vibrant, chaotic abstract for a Uranus type. It beats using generic clip art, and you can instantly use the platform's background removal to drop the art right into your chart.
Reading the Result: The 12 Star Types
With six planetary bases and two polarities, the system yields twelve distinct temperament types. What do they actually mean?
The base star dictates your core operating system—your values, your fatal flaws, and how you process the world around you.
- Saturn: The idealists. Highly principled, deeply stubborn, and prone to living in their own heads. They are driven by a sense of justice but struggle to translate their lofty ideas into practical reality.
- Venus: The hedonists. Action-oriented, flashy, and constantly chasing the next exciting experience. They are the life of the party but run from deep emotional commitments.
- Mars: The eccentrics. Fiercely independent, socially awkward, and operating on a completely different wavelength from the rest of society. They thrive in isolation and crumble under micromanagement.
- Uranus: The emotional anchors. Deeply invested in family and relationships. They are incredibly loyal but prone to suffocating those they love with their overbearing need for connection.
- Jupiter: The traditionalists. Methodical, cautious, and relentlessly hard-working. They build empires brick by brick, but entirely lack spontaneity and struggle to adapt to sudden changes.
- Mercury: The empire builders. Charismatic, fiercely ambitious, and highly focused on financial success. They are brilliant networkers but often achieve their wealth at the expense of their familial ties.
The polarity (Plus or Minus) acts as a modifier to these core traits. Plus types project their energy outward; they are active, aggressive, and highly visible. Minus types process their energy inward; they are passive, defensive, and strategic. A Venus Plus will drag you to a crowded nightclub and buy out the bar; a Venus Minus will host an exclusive, perfectly curated dinner party where they control the guest list.
What to Do Once You Know Your Type
Personality analysis is just the appetizer. The true brutalist architecture of Six-Star Astrology lies in its timing framework.
Once you know your exact star type and polarity, you unlock your position in the Destiny Cycle—a repeating twelve-year track of fortune and disaster. Every star type moves through this cycle at a different pace. While a Jupiter Plus is enjoying the peak of their "Fulfillment" year, reaping the rewards of a decade of hard work, a Mars Minus might be drowning in the absolute rock-bottom phase known as the Great World Kill (Daisakkai).
This is what made Hosoki's system a cultural phenomenon. The Daisakkai is a brutal three-year winter period where your luck completely evaporates. During these three years, the system advises you to freeze: do not start a business, do not get married, do not move houses, and do not make major life changes. Knowing your star type allows you to map out your next decade. It tells you exactly when to strike and, crucially, when to lock your doors, keep your head down, and wait out the storm.
It also unlocks compatibility readings. Because each star type has a fixed nature, the system dictates exactly how your Saturn Minus energy will clash with your partner’s Mercury Plus ambition. It strips away the romantic illusion that "love conquers all" and replaces it with cold, hard elemental friction.
You now possess the exact mathematical formula that built a multi-million-dollar publishing empire and terrified Japanese television audiences for two decades. The math is simple, but the lookup tables for the Destiny Number are undeniably tedious. Now that you have done it by hand and proven the mechanics to yourself, you have earned the right to take the shortcut. Use a digital calculator for your friends, your coworkers, and your enemies. Just remember that behind every instant result is a rigid, inescapable arithmetic.
Sources
- Uranao: "What Is Six-Star Astrology? A Complete Guide to Hosoki's System" (May 2026)
- The Hell Lady's Guide to Destiny: Unpacking Kazuko Hosoki's Six Star Astrology (May 2026)
- Fujingaho: "Hosoki Kaori's Six-Star Astrology: Know Your Destiny Star" (December 2024)