Hammer Fist

Family

Translation: hammer fist

Range & classification

Overview

A strike delivered with the bottom of the closed fist (the ulnar side), swinging the fist in a downward or horizontal arc like a hammer.

Also known as

Tetsui UchiJP^[1]Fist Hammer^[2]Bottom Fist^[3]

Used in

MMA Krav Maga Karate Kung Fu Hapkido

History & Origin

The hammer fist (tetsui uchi in Japanese) is one of the most instinctive striking techniques, using the bottom of the closed fist in a hammering motion. ^[1] Nakayama documented the hammer fist as tetsui uchi in Best Karate, noting that it was one of the oldest striking techniques in karate and appeared in the earliest Okinawan kata. ^[2] The hammer fist's ergonomic advantage — striking with the dense metacarpal bones rather than the fragile knuckles — made it a preferred technique in systems where bare-knuckle striking was standard. ^[1] In MMA, the hammer fist became prominent as a ground-and-pound weapon, particularly from mount and guard positions where conventional punches risk wrist injury. ^[3]

Country of origin· shown in random order

BrazilMMA
USAMMA
IsraelKrav Maga
Japan鉄槌打ち(Tettsui-uchi)Karate
ChinaKung Fu
KoreaHapkido

Effectiveness

The hammer fist strikes downward or sideways with the bottom of the closed fist. ^[1],[2]

Lineage

Hammer fists are found in many martial arts and are particularly effective in MMA ground-and-pound. ^[1]

Competition Record

Hammer fists are one of the most commonly used ground strikes in MMA. ^[1]

Images

No images yet for this technique.

Biomechanical Mechanism

Primary Action — Ballistic extension of the arm — kinetic chain transfers force from the ground through the hips to the fist

Joints Involved — Shoulder (flexion/rotation), elbow (rapid extension), wrist (stabilised on impact), hips (rotation)

Force Vector — Linear (jab, cross) or circular (hook, overhand) depending on the punch type

Kinetic Chain — Ground reaction force → hip rotation → torso rotation → shoulder extension → fist impact — each link amplifies velocity

Position & Entry

From fighting stance — Establish guard, generate force through hip rotation and weight transfer, extend the striking arm to the target

As combination (after setup) — Follow a jab or feint with the punch to exploit the opening created

As counter — Time the punch to land as the opponent commits to their own attack

Videos

TeachMeGrappling Coach Brian

Hammer Fist to Setup the KICK!

Hammer Fist·TeachMeGrappling Coach Brian

This video Majid demonstrates a hammer fist that you can use as a strike or a grab to setup a kick to the face. Check o…

1 video

Learn This Technique

No instructional courses yet for this technique.

Ratings

Danger Rating

Risk of injury to the person this technique is applied to

High5/10

Fleshy fist edge strike; common in ground-and-pound

Difficulty

Skill level needed to execute this technique reliably

Beginner

Competition Legality

Whether this technique is allowed under major competition rule sets

Illegal

WBC/Boxing — Only closed-fist punches permitted {src— WBC Rules of Boxing}

Kyokushin — Only closed-fist strikes to body permitted {src— IKO Kyokushin Tournament Rules}

— WT — Prohibited

WT Competition Rules 2024PDF

— WAKO — Closed fist only

WAKO Competition RulesPDF

K-1/GLORY — Closed fist only {src— K-1/GLORY Kickboxing Rules}

Restricted

— WKF — Varies by technique — some open-hand strikes legal ...

WKF Competition Rules 2024PDF

— ITF — Some knife hand techniques legal

ITF Competition RulesPDF

Legal

— palm strikes, slaps permitted

Unified Rules of MMA, August 2025PDF

— IFMA — Legal — palm strikes permitted in Muay Thai

IFMA Muay Thai RulesPDF

Training Notes

✓The hammer fist strikes with the bottom of the closed fist — the fleshy pad below the little finger

✓Swing the fist in a downward, horizontal, or diagonal arc like swinging a hammer

✓The hammer fist is one of the safest strikes for the attacker because the impact area is padded and the wrist stays aligned

✓It is a primary ground-and-pound weapon in MMA — from mount or guard, hammer fists can be thrown repeatedly without wrist injury risk

✓The hammer fist is also effective standing: as a downward strike to the top of the head, or horizontal to the temple

✓No hand wraps or gloves are needed — the hammer fist is a bare-hand striking technique used in self-defence

✓In MMA, fighters like Mark Hunt and Fedor Emelianenko used devastating ground-and-pound hammer fists to finish opponents

Common Mistakes

!Hitting with the knuckle side of the fist instead of the bottom pad — this negates the safety advantage

!Swinging too wide and losing accuracy — the hammer fist should follow a controlled arc

!Not using the shoulder and core to power the strike — arm-only hammer fists lack force

!Throwing hammer fists from outside range where a punch would be more effective

!Not maintaining position during ground-and-pound — the priority is control first, strikes second

!Using the hammer fist at a flat angle where it bounces off the guard — aim for gaps and angles

!Winding up visibly before striking, giving the opponent time to cover or escape

Related Techniques

Combination — multi-strike sequence incorporating this technique for higher effectiveness

Counter Techniques

Block — absorb the strike with a protective guard position Evasion — move the target out of the strike's path Counter-Attack — time an offensive response during the recovery phase of the strike

Setup Chain

1Assume Fighting Stance — begin from a balanced position with guard up

2Generate Power — use hip rotation and weight transfer for maximum force

3Execute Strike — deliver the technique to the target with correct form

4Recover to Guard — return immediately to defensive position

Sources & References

Primary Source

Karate-Do Kyohan: The Master Text (Gichin Funakoshi, 1935)

1BookKarate-Do Kyohan (Funakoshi, 1935)

Alias sources — [1] Dynamic Karate (Nakayama, 1966) [2] Dynamic Karate (Nakayama, 1966) [3] Dynamic Karate (Nakayama, 1966)

2BookMastering Jujitsu (Gracie & Danaher, 2003)

History sources — [1] The Art of Striking (Blauer, 2004) [2] Best Karate Vol. 3 (Nakayama, 1978) [3] Ultimate MMA Conditioning (Jamieson, 2009)

3SyllabusJapan Karate Association (JKA) — Official Technical Terminology

Official karate technique names (和語/漢語)

4OtherJapanese Martial Arts Standard Terminology (武道用語)

Established Japanese martial arts naming convention — native Japanese term (和語/漢語)

5CitationKarate-Do Kyohan (Funakoshi, 1935)

Alias sources — [1] Dynamic Karate (Nakayama, 1966) [2] Dynamic Karate (Nakayama, 1966) [3] Dynamic Karate (Nakayama, 1966)

6CitationMastering Jujitsu (Gracie & Danaher, 2003)

History sources — [1] The Art of Striking (Blauer, 2004) [2] Best Karate Vol. 3 (Nakayama, 1978) [3] Ultimate MMA Conditioning (Jamieson, 2009)

Community

Athletics

Requires

hand speed, hip rotation, wrist alignment on impact

Favours

proportional reach, strong wrists, fast-twitch shoulder muscles

Key muscles

deltoids, pectorals, triceps, core rotators, forearms

Sub-techniques

Find by what a technique does — not its name

Every move, in any martial art, shares a few universal traits. Mix and match below to pinpoint the right tool — or compare equivalents across styles.

Downward Hammer Fist

SubFamily

A hammer fist driven straight downward onto the target, commonly used in ground-and-pound positions or against a bent-over opponent.

1 genera·1 techniquesExplore

Horizontal Hammer Fist

SubFamily

A hammer fist swung in a horizontal or lateral arc, using the bottom of the fist to strike the temple or side of the head in a sweeping motion.

1 genera·1 techniquesExplore

Notes

The hammer fist appears in 156 passages across 39 books. Uses the bottom of the closed fist in a swinging motion — like swinging a hammer. The safest striking surface (lowest self-injury risk). Dominant ground-and-pound weapon in MMA because there is no risk of breaking knuckles on the skull. (39 books; MMA training manuals)

Frequently Asked Questions

How can I use the hammer fist to set up other techniques?

Coach Brian from TeachMeGrappling demonstrates using the hammer fist as part of a combination to open up kicks and other strikes. The sequence typically flows from a jab into the hammer fist, which then leads into your next offensive move.

What's the difference between throwing a traditional hammer fist and using it in combination?

Instead of throwing a traditional hammer fist in isolation, Coach Brian emphasizes throwing a jab first, then bringing the hammer fist back as a strike, which also sets you up for a grab or follow-up technique.

How does the Hammer Fist work?

A strike delivered with the bottom of the closed fist (the ulnar side), swinging the fist in a downward or horizontal arc like a hammer.

Where does the Hammer Fist come from?

The hammer fist (tetsui uchi in Japanese) is one of the most instinctive striking techniques, using the bottom of the closed fist in a hammering motion. Nakayama documented the hammer fist as tetsui uchi in Best Karate, noting that it was one of the oldest striking techniques in karate and appeared in the earliest Okinawan kata.

Is the Hammer Fist legal in competition?

Unified MMA: legal — Legal (palm strikes, slaps permitted); WBC/Boxing: banned — Only closed-fist punches permitted; WKF: restricted — Varies by technique — some open-hand strikes legal in kata, generally restric…; Kyokushin: banned — Only closed-fist strikes to body permitted; WT: banned — Prohibited; ITF: restricted — Some knife hand techniques legal; WAKO: banned — Closed fist only; K: banned — 1/GLORY — Closed fist only; IFMA: legal — Legal — palm strikes permitted in Muay Thai

How dangerous is the Hammer Fist?

Danger rating 5/10. High — fleshy fist edge strike; common in ground-and-pound

How do I set up the Hammer Fist?

The standard setup chain: Assume Fighting Stance → Generate Power → Execute Strike → Recover to Guard.

How do I defend against the Hammer Fist?

Standard counters include: Block — absorb the strike with a protective guard position / Evasion — move the target out of the strike's path / Counter-Attack — time an offensive response during the recovery phase of the strike.

What are the variants of the Hammer Fist?

Common variants: Overhead hammer fist (bringing the fist straight down onto the target from above); Side hammer fist (swinging horizontally using the bottom of the fist); Ground-and-pound hammer fist (delivered from mount or top position on the ground).

How effective is the Hammer Fist in competition?

Hammer fists are one of the most commonly used ground strikes in MMA.

What are common mistakes when doing the Hammer Fist?

Top errors to watch for: Hitting with the knuckle side of the fist instead of the bottom pad — this negates the safety advantage / Swinging too wide and losing accuracy — the hammer fist should follow a controlled arc / Not using the shoulder and core to power the strike — arm-only hammer fists lack force / Throwing hammer fists from outside range where a punch would be more effective.

What are other names for the Hammer Fist?

The Hammer Fist is also known as Tettsui-uchi, Tetsui Uchi, Fist Hammer, Bottom Fist.

bottom fist downward ground-and-pound durable