CHIBA — With oil prices hitting new highs, producing eco-friendly and fuel-efficient cars has become the norm for most carmakers.

But the new models unveiled to the press Wednesday for the 40th Tokyo Motor Show at the Makuhari Messe convention center show automakers also feel future cars must be cute and easy to drive.

This year's show, which opens to the public Saturday, is the first in 10 years to feature both general and commercial vehicles. The 241 participating companies, hailing from 11 nations and a region, are displaying 542 vehicles, including 77 making world premieres and 103 appearing for the first time in Japan. Many are concept cars.

Among them are Toyota Motor Corp.'s RiN, which aims to please its occupants with comfortable, posture-enhancing heated seats and an oxygen-level conditioner.

Focusing more on the environment is Toyota's 1/X hybrid, which weighs only 420 kg, or one-third the weight of the Prius, thanks to the use of carbon fiber reinforced plastic in its body frame.

"By reducing the weight to one-Xth (of other cars), we are aiming to increase energy efficiency by X times," Toyota President Katsuaki Watanabe said. "It is twice as fuel-efficient compared with the Prius."

If fuel-efficiency is key, creating a smaller car may be the answer, which is what Toyota's iQ Concept is all about. The car is less than 3 meters long but can still hold three adults and a child.

Reflecting Japan's infatuation with robotics, Nissan Motor Co. unveiled the Pivo2. Powered by lithium-ion batteries, it features a "robot" that predicts the driver's emotions through voice- and facial-recognition technology. The robot, fixed near the center of the dash, talks and makes suggestions to keep the driver happy. The car's round body rotates 360 degrees, making it easier to change directions.

"Since in-wheel motors eliminate the axles and steering rack, we gain an almost limitless freedom of mobility," Nissan President Carlos Ghosn said. The car is equipped with flexible fuel technology, which allows it to run on gasoline, ethanol or a mix of both.

Honda Motor Co. meanwhile showed off the Puyo, a unique fuel-cell vehicle covered with a gel-like exterior intended to make it feel like an "adorable pet."

"The car is covered with silicone material that people would want to touch," said Honda President Takeo Fukui.

The car, which is steered with a joystick rather than a wheel, also allows the driver to rotate 360 degrees to change directions.

For those with the need for speed, Toyota offers the FT-HS, a next-generation hybrid sports car with a 3.5-liter V-6 engine. The rear-wheel drive car is equipped with large tires that are wider in the rear and a hybrid system that allows drivers to reduce harmful emissions.

In a much-anticipated move, Nissan unveiled its new GT-R supercar, which it says embodies all the expertise needed to develop the ultimate car. The GT-R, previously known as the Skyline GT-R, is powered by a 3.8-liter twin turbo V-6 engine that can whisk drivers from zero to 100 kph in 3.6 seconds.

The show, which runs through Nov. 11, will also let visitors try out five test-driving courses on the premises or at the adjacent Makuhari Kaihin Koen.