NGK traces its origins to 1919, when NGK Corporation (originally NGK Insulators, Ltd.) was established in Nagoya, Japan as a manufacturer of ceramic insulators for electric power systems. [1]

In 1930, the company began manufacturing spark plugs under the “NG Spark Plug” name, which became NGK Spark Plug in 1934. As demand grew, a separate company, Niterra Co., Ltd., was founded in 1936 to focus on spark plugs and automotive components. [2]

In 2023, NGK Spark Plug Co., Ltd. officially changed its corporate name to Niterra Co., Ltd. to reflect its expansion beyond spark plugs into electronics, sensors, ceramics, and medical technologies. Despite the corporate name change, the NGK brand remains in use worldwide for spark plugs and many automotive products. [3]

Separately, the original NGK Insulators company rebranded to NGK Corporation in 2026 while continuing its focus on industrial ceramics and energy technologies. [4]

The abbreviation NGK comes from the Japanese company name:

Nihon Gaishi Kabushikigaisha (日本碍子株式会社)

which translates to Japan Insulator Co., Ltd.

• Country: Japan

• City: Nagoya, Aichi Prefecture

• Founded: 1919 (NGK Corporation)

• Automotive business founded: 1936 (now Niterra)

NGK is widely known for manufacturing:

• Spark plugs

• Iridium spark plugs

• Ruthenium spark plugs

• Glow plugs (diesel engines)

• Ignition coils

• Oxygen (O2) sensors

• Air-fuel ratio sensors

• Exhaust gas temperature sensors

• Knock sensors

• Automotive electronics

• Technical ceramics

• Ceramic cutting tools

• Industrial sensors

NGK offers several spark plug series designed for different applications.

Copper Spark Plugs

• Standard nickel electrode

• Affordable

• Reliable for daily driving

• Typically replaced every 20,000–30,000 km

Platinum Spark Plugs

• Longer service life

• Better wear resistance

• Suitable for modern engines

Iridium IX

One of NGK’s most popular performance spark plugs.

Features:

• Fine-wire iridium center electrode

• Improved ignition

• Better throttle response

• Long lifespan

• Commonly used in motorcycles and performance vehicles

Laser Iridium

Designed primarily for OEM applications.

Features:

• Laser-welded iridium center electrode

• Platinum ground electrode

• Excellent durability

• Service life often exceeding 100,000 km under normal conditions

Ruthenium HX

NGK’s newest premium technology.

Advantages include:

• Higher ignition efficiency

• Improved durability

• Better resistance to wear

• Optimized for modern turbocharged and direct-injection engines

Beyond spark plugs, NGK is a major producer of engine-management sensors, including:

• Oxygen sensors

• Wideband air-fuel ratio sensors

• NOx sensors

• MAP and pressure sensors

• Exhaust gas temperature sensors

These sensors help reduce emissions, improve fuel economy, and optimize engine performance.

NGK products are supplied as original equipment to many global vehicle manufacturers, including:

• Toyota

• Honda

• Nissan

• Mazda

• Subaru

• Mitsubishi Motors

• Suzuki

• Yamaha Motor

• Kawasaki Motors

• BMW

• Mercedes-Benz

• Volkswagen

• Hyundai

• Kia

OEM fitment varies by vehicle model and engine.

NGK products are sold in more than 100 countries, with manufacturing facilities and technical centers across:

• Japan

• United States

• Germany

• France

• United Kingdom

• China

• Thailand

• Indonesia

• India

• Brazil

• Mexico

• South Africa

• Australia

The broader NGK group employs nearly 20,000 people worldwide. [5]

NGK has earned a strong reputation for:

• High manufacturing quality

• Reliable ignition performance

• Long service life

• OEM-grade engineering

• Strong research and development in ceramic materials

Its spark plugs are widely recommended by mechanics and automotive manufacturers for both standard replacement and performance applications.

NGK’s expertise in advanced ceramics extends into:

• Power transmission insulators

• Semiconductor manufacturing components

• Energy storage systems

• Environmental technologies

• Industrial filtration

• Electronic ceramics

• Medical and sensing technologies

These businesses leverage the company’s long-standing ceramic engineering capabilities. [6]

NGK emphasizes innovation through ceramic technology with a focus on:

• Environmental sustainability

• Carbon neutrality

• Advanced mobility

• Digital society technologies

• High-quality manufacturing (Monozukuri)

The company continues to invest in next-generation materials, sensors, batteries, and energy solutions while maintaining the NGK brand’s legacy in automotive ignition products. [7]

1. History | About NGK | NGK Corporation

2. Corporate Outline | About NGK | NGK Corporation

3. Niterra History – A Long History Since 1936

4. NGK INSULATORS Becomes NGK

5. About NGK | NGK Corporation

6. Message from the President | About NGK | NGK Corporation

7. Business Overview | About NGK | NGK Corporation