Science-Based Golf Biomechanics
Developed by Sōichi Hiroto – decades of practice, more than 500,000 people supported according to his publisher
Get a first indication of your movement type in just 2 minutes with our free Quick Test.
Start Free Quick Test →The 4-Stance Theory is a revolutionary biomechanical framework developed by Sōichi Hiroto. It categorizes human movement into four innate types: A1, A2, B1, and B2. Every person is born with a specific 'physical operating system' that determines how they should optimally stand, move, and stabilize. In golf, this means: There is no 'one perfect swing' – there is the perfect swing for YOUR body type.
Traditional golf instruction teaches everyone the same techniques – ignoring that every body has its own biomechanical blueprint. That's why so many golfers plateau, get injured, or never reach their potential.
When you train movement patterns that contradict your innate body type, every swing requires extra muscular effort. You're literally working against your own anatomy – exhausting yourself for suboptimal results.
Under pressure, your body reverts to natural patterns. If your trained swing contradicts your type, you'll see wild inconsistency exactly when it matters most – in tournaments or important rounds.
Years of forcing unnatural movement patterns create repetitive stress on joints, tendons, and muscles. Back pain, elbow problems, and shoulder issues are often the result of type-inappropriate training.
The 4-Stance approach identifies your innate movement type and builds training around it. Instead of fighting your biomechanics, you use them – for a swing that feels natural, is repeatable, and sustainable for decades.
From Japanese Sports Medicine to Golf Revolution
Born in Tokyo, Japan
First research and treatment center for biomechanical movement analysis
Member of the strengthening staff of the Japanese Olympic Committee (JOC)
Japan Golf Tour Organization integrates 4-Stance Theory into professional training
Head of the sports body therapy practice “Hiroto Dojo” and further development of the REASH Theory
The Reash Theory and 5-Point System
The Reash Theory (レッシュ理論) is Sōichi Hiroto's overarching biomechanical framework. It encompasses the 4-Stance Theory as well as the 5-Point Theory and Bone Logic.
The 5-Point Theory identifies five body points that form the body axis and serve as the starting point for every movement:
Base of the neck, head-torso connection
Center of upper body, axis of rotation
Hip joints (left & right), power transfer
Knee joints (left & right), stabilization
Ankle joints & soles (left & right), grounding
When these five points are vertically aligned, they form a stable body axis. The 4-Stance types differ in HOW these points are naturally aligned.
The 4 types result from the combination of two axes:
This results in 4 combinations: A1 (Front-Inside), A2 (Front-Outside), B1 (Back-Inside), B2 (Back-Outside)
Individual Biomechanics Instead of One-Size-Fits-All
Your body type is genetically determined and doesn't change. Working against it leads to inefficiency and injuries.
Movements that match your type require less muscular effort for better results. That's the difference between 'working hard' and 'working smart'.
Chronic golf injuries often result from years of training against your own body type. Type-appropriate training protects joints and musculature.
The different swing styles of top professionals are often associated with different 4-Stance types:
Rotation around a vertical axis, stable base, powerful arm swing – often classified as an A2 Parallel type
Dynamic, large arc, diagonal weight shift – often classified as a B2 Cross type with heel base
Rotation-based, high finish, diagonal power transfer – often classified as an A1 Cross type
Further Information and Sources
6 simple questions will give you an initial indication of your probable 4-Stance type
The 4 types result from two characteristics: center of gravity front/back (A = forefoot, B = heel) and inner/outer (1/2). The combination determines the movement pattern: A1 and B2 move in the Cross pattern, A2 and B1 in the Parallel pattern.
A1 (Cross), A2 (Parallel)
B1 (Parallel), B2 (Cross)
A1 (Toes), B2 (Heels)
A2 (Toes), B1 (Heels)
Biomechanics, golf characteristics, and practical tips for each type
Shoulder-width stance with 55-60% weight on the inside edge of the forefoot (ball of the big toe). Think Adam Scott's balanced setup - feet feel 'grounded' through the balls of the big toes.
Tall, athletic posture with spine tilt away from target (5-7°). Minimal hip hinge (20-25°). Arms hang naturally, creating space for rotational power. Reference: Hideki Matsuyama's upright address.
Weight distribution favors front foot (55/45). Feel pressure on inside edges of both feet, particularly the big toe pad. This 'inner rail' creates the foundation for cross-pattern rotation.
Slightly wider than shoulder-width with 50-55% weight on outer edge of forefoot (little toe area). Think Tiger Woods' powerful, stable base - feet feel 'planted' on outer balls of feet.
Athletic posture with moderate hip hinge (30-35°). Spine neutral or slight forward tilt. Lower body feels 'locked in' from the start. Reference: Justin Thomas' stable, powerful address position.
Even weight distribution (50/50) with pressure on outer forefoot rails. This creates the stable platform needed for the linear power delivery that defines A2 swings.
Shoulder-width stance with 50-55% weight on inner heel (inside of heel bone). Think Sergio Garcia's grounded setup - feet feel 'rooted' through the inner heels into the ground.
Deeper knee flex (25-30°) with more forward spine tilt (35-40°). Lower center of gravity than A-types. Arms hang slightly closer to body. Reference: Sergio Garcia's compact, athletic address.
Even or slightly back-weighted (50/50 to 45/55 rear). Pressure concentrated on inner heel rails of both feet. This 'grounded' position creates the stable base for linear, repeatable mechanics.
Wider than shoulder-width (1.5x shoulder width) with 55-60% weight on outer heels. Think Phil Mickelson's wide, powerful base - feet feel 'spread' and grounded on outer heel edges.
Athletic posture with moderate knee flex (20-25°) and spine tilt away from target (8-12°). Arms hang with room for the large swing arc. Reference: Bubba Watson's dynamic, athletic setup.
Weight distribution favors rear foot (55/45 to 60/40 back). Pressure on outer heel rails. This 'loaded back' position sets up the powerful weight transfer that defines B2's distance.
Understand the differences between the various stance types
Both types are forefoot-based (A), but differ fundamentally in movement pattern. A1 uses cross-pattern with diagonal force transfer – energy flows from the inner forefoot diagonally through the body. This enables powerful rotation around the spine with a high, complete follow-through. A2, on the other hand, uses parallel-pattern with linear force transfer and single-axis rotation. The A2 swing is more direct, steeper, and more precise, with a more stable lower body and more controlled ball flight.
Both types are based on heel loading (B), but use completely different movement patterns. B1 uses parallel-pattern – compact, grounded, with minimal lateral movement. The B1 swing is consistent and repeatable, perfect for precision. B2 uses cross-pattern with dynamic, powerful two-axis movement. The B2 swing creates large arcs and maximum distance through pronounced weight transfer from back to front. B1 is the compact precision player, B2 is the powerful long hitter.
Both types use the inner balance line (1), but have different center of gravity bases. A1 is forefoot-based with cross-pattern – rotation-driven with a high, complete finish. The movement is upright and around a central axis. B1 is heel-based with parallel-pattern – grounded, compact, with a lower finish. A1 generates power through rotation, B1 through grounded stability and precise repeatability.
Both use the outer balance line (2), but differ in base and pattern. A2 is forefoot-based with parallel-pattern – linear, direct swing with steep attack angle. The A2 swing is known for precision and control. B2 is heel-based with cross-pattern – powerful with large arc and maximum weight transfer. B2 is the power type for long drives, A2 is the precision type for controlled iron shots.
Both use cross-pattern (1+2 = diagonal), but have different center of gravity bases. A1 is forefoot-based with upright position and the front foot as the axis. The swing is elegant and rotation-driven. B2 is heel-based with two-axis movement and powerful weight transfer. The B2 swing generates more lateral movement and larger arcs for maximum distance. Both are powerful types, but A1 through rotation, B2 through transfer.
Both use parallel-pattern (2+1 = linear), but differ in base. A2 is forefoot-based with more stable lower body and steep attack angle – ideal for precision. The A2 swing is direct and controlled. B1 is heel-based with grounded position and compact swing – perfect for repeatability. Both types are known for consistency and control, but A2 with forefoot-based dynamics, B1 with heel-based stability.
The same golf swing, taught to two different types, produces completely different results. Understanding this is the key to unlocking your potential.
An A1 golfer (rotation-based), trying to copy Tiger Woods' A2 (linear) swing mechanics:
The same A1 golfer learning type-appropriate techniques from Adam Scott's or Hideki Matsuyama's swing:
This is why two golfers can receive identical instruction, yet one thrives while the other struggles. It's not about talent or effort—it's about the match between training and innate body type.
After decades of practice and more than 500,000 people supported, Sōichi Hiroto recognized what traditional sports science missed: there are four distinct ways humans are built to move.
Sōichi Hiroto (廣戸聡一), born in Tokyo in 1961, is a Japanese sports body therapist, head of the sports body therapy practice “Hiroto Dojo”, and the founder of the comprehensive body theory known as REASH Theory. After studying bodywork therapy, he founded the Hiroto Dojo in 1989, where he began treating elite athletes from various disciplines – from professional baseball players and Olympic gymnasts to J-League soccer stars and touring golfers.
Through decades of hands-on practice with more than 500,000 people supported according to his publisher – observing how different athletes moved, where they held tension, and why some techniques worked for certain individuals but not others – Hiroto made a groundbreaking discovery: there is no single 'correct' way to move. Instead, humans are born with one of four distinct movement types, each with its own optimal biomechanical patterns.
1961 in Tokyo, Japan
Hiroto Dojo (1989)
Head of the sports body therapy practice “Hiroto Dojo”
More than 500,000 (according to publisher)
Hiroto expanded his knowledge by studying with world-class coaches across different sports
February 2000
Studied boxing training methods under Kevin Rooney, the legendary coach who trained Mike Tyson. This experience deepened his understanding of power generation and movement efficiency across different body types.
March 1998
Participated in the Atlanta Braves spring training, studying under head coach David Paisley. Observed how MLB athletes with different body types responded to standardized vs. individualized training.
Born in Tokyo, Japan. Early interest in sports and martial arts shaped his curiosity about human movement.
Founded Hiroto Dojo (廣戸道場) after studying bodywork therapy. Began systematic research on movement patterns in elite athletes.
International training: Atlanta Braves spring camp (1998) and Cus D'Amato Boxing Gym with Kevin Rooney (2000).
Appointed JOC (Japanese Olympic Committee) Strengthening Staff. Also became advisor to JGTO and Chiba Lotte Marines (2013).
Heads the sports body therapy practice “Hiroto Dojo”. Continues teaching, research, and developing REASH Theory applications.
Hiroto realized that forcing an athlete into a movement pattern that contradicts their natural type leads to injury, performance plateaus, and chronic pain. He codified these observations into the 'REASH Theory' (レッシュ理論), which includes the 4-Stance Theory, the 5-Point Theory, and Bone Logic (骨理学).
Biomechanical principles based on skeletal structure, joint alignment, and natural movement axes
Four innate center-of-gravity types (A1, A2, B1, B2) determine optimal stance, posture, and weight distribution
Your movement type is innate – like blood type, it cannot be changed, only optimized
Hiroto's work has transformed how professional sports organizations approach athlete development. His theories are now integrated into training programs across Japan and increasingly worldwide, from Olympic committees to professional golf tours.
People Supported
Years of Research & Practice
Global Impact
How Hiroto's theory is transforming golf at the highest levels
Shinichi Yokota was a promising JGTO pro who won his first tour event, the ANA Open, in 1997. But after that victory, he went 13 years without another win – despite keeping his tour card. Everything changed when he met Hiroto and discovered he was a B2 type who had spent his entire career training with A-type techniques.
I spent 13 years copying other players' swings. When I finally understood my own body type and stopped fighting against my natural movement patterns, everything clicked. I no longer had back pain. My drives went further. And in 2010, I won my second tour event – the Canon Open. I wasn't more talented than before. I was finally moving the way my body was built to move.
— Shinichi Yokota, JGTO Pro
Years
Winless
4-Stance
4-Stance Adopted
2010
Tour Victory
The Japan Golf Tour Organization (JGTO) officially integrated 4-Stance principles into its young professional development camps. Players who aligned their technique with their natural stance type reported progress in consistency and resilience.
improved swing consistency
reduction in training injuries
performance progress
Received the prestigious 'Lesson of the Year' award from Golf Digest Japan for his revolutionary 4-Stance golf instruction methodology.
Official member of the Japanese Olympic Committee's athlete enhancement program, advising Olympic athletes across various disciplines.
Sōichi Hiroto has authored numerous books on 4-Stance Theory and biomechanics
Jitsugyo no Nihon Sha
The definitive guide to understanding and applying 4-Stance Theory in all aspects of movement and sport.
Gakken Plus
Comprehensive application of 4-Stance principles specifically for golf, with type-specific swing instructions.
Jippi Compact
How to identify and leverage your stance type to generate maximum power with minimum effort.
Jitsugyo no Nihon Sha
Get better without swinging! Body training and movement exercises based on your 4-Stance type.
Everything you need to know about 4-Stance Theory and Golf4Stance
The 4-Stance Theory is a biomechanical concept stating that every person is born with one of four natural movement types (A1, A2, B1, B2). These types determine how we shift our body weight, how we stand, and how we move most efficiently. In golf, this means: There isn't 'one' perfect swing, but the perfect swing for YOUR type.
Golf4Stance offers two ways: Our AI-powered chat assessment guides you through a natural conversation about your movement habits. Alternatively, you can use our structured assessment with targeted biomechanical tests. Both methods take only a few minutes and provide you with your result (A1, A2, B1, or B2) immediately.
Training that matches your natural movement type feels easier and more natural. The benefits are: 1) Faster learning progress because you're not working against your body. 2) Higher consistency and precision. 3) Significantly reduced risk of injury by avoiding biomechanical stress. 4) More driving distance through more efficient power transfer.
Absolutely! Especially for beginners, it is crucial to learn 'correctly' for your own body from the start, rather than having to correct laboriously learned, unsuitable patterns later. Our plans adapt to your level – from complete beginner to single handicapper.
The main difference lies in the center of gravity: A-types (A1, A2) have their center of gravity more on the forefoot and are 'extension' types that stabilize through extension. B-types (B1, B2) have their center of gravity more on the heel and are 'flexion' types that generate stability through flexion and ground contact.
The entire app is completely free! The assessment for type determination, access to the dashboard, all training plans, and special injury prevention programs are all available at no cost. If the app helps you, we'd be delighted with a voluntary donation.
The theory was developed by Japanese sports body therapist Sōichi Hiroto. It is based on decades of research on elite athletes, musicians, and dancers. In golf, it was popularized by Shinichi Yokota and is already standard in professional training in Asia.
No, and you shouldn't! Your stance type is innate and does not change throughout your life. It is your 'biomechanical fingerprint'. Attempts to change the type often lead to performance drop, frustration, and injuries. The goal is to master your own type.
No, you only need your normal golf equipment. For fitness exercises at home, your own body weight is usually sufficient; sometimes simple aids like a resistance band or dumbbells are helpful but not mandatory. Our plans are designed to be flexible.
Our AI engine analyzes your profile (stance type, age, level, goals) and accesses a database of hundreds of type-specific exercises. It intelligently assembles these into a progressive plan that optimally manages load and recovery to achieve maximum results.
No. Your 4-Stance type is innate – similar to your blood type – and remains constant throughout your life. However, you can learn to work WITH your type instead of against it.
That's normal! Many people show characteristics of multiple types, especially if they've trained against their natural type for years. Our AI-powered analysis identifies your dominant type precisely.
No! The 4-Stance theory is not about complete swing reconstruction, but about OPTIMIZATION. You adjust small but crucial elements to your type – setup, weight distribution, movement pattern. The result: More power with less effort.
There is no 'best' type! Each type has strengths: A1 for powerful rotation, A2 for precision, B1 for consistency, B2 for distance. Top professionals exist in all 4 types. The best type is YOUR type – when you use it optimally.
The 4-Stance Theory, developed by Japanese sports body therapist Sōichi Hiroto, revolutionizes how golfers approach their stance and swing mechanics. This scientifically-backed methodology identifies four distinct stance types (A1, A2, B1, B2) based on individual biomechanics and natural movement patterns.
By understanding your unique stance type, you can optimize your golf swing, reduce injury risk, and achieve consistent performance improvement. Our AI-powered assessment analyzes your physical characteristics and movement preferences to determine your ideal stance configuration.
Thousands of golfers worldwide have transformed their game using 4-Stance principles. Whether you are a beginner looking to build proper fundamentals or an experienced player seeking performance optimization, personalized training based on your stance type delivers measurable results.
Can't find what you're looking for? Our AI-powered assessment will analyze your unique golf stance and provide personalized answers tailored to your needs.
