We still don't know what exactly the bright minds at Mazda are up to with regards to a new RX-branded sports car, but the Japanese automaker hasn't been shy about patenting some interesting things. For example, Mazda most recently patented Aston Martin-like doors.

Why? We don't know, but they open in a similar swan fashion as Aston Martins—15 degrees to be exact, per the patent's description. These types of doors often allow for easier exit and entry, especially when the car sits lower to the ground. Doors that open straight out have a tendency to bang into curbs or other parking barriers.

Of course, the most optimistic reason behind this patent is that a new Mazda sports car is on the horizon, maybe even an RX-9. Rumors have persisted the past few years over a new Mazda RX sports car, though the automaker has been quiet on future sports car plans. Mazda has, however, not denied that its engineers continue to work with the rotary engine in an effort to refine it and ensure it meets emission standards. Rotary engines aren't the most fuel-efficient designs—and they love to drink oil.

Mazda RX-Vision concept, 2015 Tokyo Motor Show

Mazda RX-Vision concept, 2015 Tokyo Motor Show

Mazda RX-Vision concept, 2015 Tokyo Motor Show

Mazda RX-Vision concept, 2015 Tokyo Motor Show

Mazda RX-Vision concept, 2015 Tokyo Motor Show

Mazda RX-Vision concept, 2015 Tokyo Motor Show

Two years ago, Mazda's research and development chief Kyoshi Fujiwara said future rotary engine plans would likely involve turbocharging over electrification to start. He didn't offer any reference as to when we may see such an engine, though.

2017 marks the 50th anniversary of Mazda's rotary-powered cars. This year's Tokyo motor show may provide a perfect backdrop for Mazda to debut its future RX sports car.