Mazda has pulled the wraps from the car that’s set to replace the popular 6 in only 18 months’ time.The four-door saloon concept will make its public debut at the Tokyo Motor Show in December, and is called the Takeri.Auto Express understands that hatchback and estate versions are also under development, but details remain scarce. However, Mazda has confirmed that the car follows its Kodo design philosophy, and features the new SkyActive-D 2.2-litre diesel engine that will debut in the CX-5 SUV in March.The 173bhp 2.2-litre engine is all new, and will return around 60mpg. Revving smoothly to 5,500rpm, it can generate up to 400Nm of torque and promises strong in-gear acceleration.As with the Minagi concept that previewed the CX-5, the Takeri is believed to be a close representation of the upcoming 6, and has been penned by chief designer Akira Tamatani.By the time the newcomer reaches production, drivers can expect it to be lighter and tougher than the car it replaces, thanks to the use of lightweight, high-tensile steels. And Mazda’s SkyActive technologies should ensure it’s also better to drive.The SkyActive approach sees every component reduced in weight, with special attention paid to the aerodynamics.Mazda claims that this helps to save fuel, and also improves the handling. Sleeker, more attractive looks are another benefit.The new 6 will also feature the company’s latest regenerative braking system, which will incorporate stop-start engine technology. In addition, it uses novel capacitors, which store electrical energy and use it to power the vehicle’s electrical equipment, including air-conditioning and headlights.This technology is being described as the second step in Mazda’s march to build an all-electric vehicle – a city car that Auto Express has learned is scheduled to arrive in 2014.The Takeri will appear on the Tokyo stands alongside Mazda’s new CX-5 and the Shinari Coupé concept, which first appeared at the Geneva Motor Show.