What is ZENDAIKYO?
ZENDAIKYO (National Council of Heavy Vehicle Repair Shops, Japan) is a council of 32 repair shops across Japan that specialise in body repair and body building for heavy trucks and buses (as of July 1, 2026). It was founded on April 20, 1979.
It is the only organization in Japan that produces standard labor-time (kosu) reference materials for heavy truck and bus repair.
Four things ZENDAIKYO does
1. Making the repair “yardstick”: kosu tables
ZENDAIKYO produces the Reference Material for Accident Vehicle Damage Assessment (kosu tables), which shows how many hours each repair job takes with standard equipment and skills. Based on the Japanese Industrial Standard JIS Z8141:2001, main work time and preparation time are added up for each part, taking into account work safety (such as work at height) and difficulty.
There is one book per truck maker: the Hino Motors edition, the Mitsubishi Fuso Truck edition and the Isuzu Motors / UD Trucks edition (published in Japanese).
2. Improving skills together
ZENDAIKYO began as a group studying how to straighten truck frames bent in accidents. Since 1986 it has held an overseas study tour every year, learning about new technology, equipment and tools from around the world. Members continue to research and train whenever new vehicle models appear.
3. Sharing information across Japan
Member shops from Hokkaido to Okinawa exchange knowledge and experience around three pillars: sharing information, mutual technical training, and introducing and developing new technology.
4. Connecting with the world
ZENDAIKYO works with AIRC (Auto Body International Repair Conference), the international conference on body repair, exchanging information on repair techniques, systems and equipment in different countries.
Who does it help?
- Repair shops: they can prepare estimates based on well-founded work hours.
- Insurance companies: a reference when assessing the repair cost of accident vehicles.
- Truck and bus operators: it is easier to check whether a repair bill is reasonable.
- Students and the general public: useful for learning how heavy vehicle repair works.
How kosu shapes the repair bill
Labor charge ＝ kosu × labor rate
Example: 2.4 h × 30,000 yen/h ＝ 72,000 yen (example figures for explanation only)
The total repair cost is this labor charge plus parts, paint materials, subcontracting and so on.
※ ZENDAIKYO does not set or recommend any labor rate amount (hourly charge). Each business decides its own rate based on its own costs.