TOKYO - Japanese automakers are going to be producing cars over the weekend and taking Thursday and Friday off to avoid blackouts from a power crunch caused by problem nuclear reactors.

Toshiyuki Shiga, chairman of the Japan Automobile Manufacturers Association and chief operating officer of Nissan Motor Co., told reporters Thursday the plan, which includes auto-parts suppliers, kicks in July, August and September _ the peak months for electricity use in Japan.

The government has asked major companies to reduce electricity use by 15 percent. The March 11 earthquake and tsunami hobbled the Fukushima Dai-ichi nuclear power plant in northeastern Japan, sending three reactors into meltdowns.

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The Hamaoka nuclear plant is also being shut down because of safety fears, further crimping energy resources.

"We need to respond with a sense of crisis to the power shortage," said Shiga, who was not wearing a tie in attire now called "super cool biz."

The practice, a notch above the regular summer month "cool biz," encourages the usually dark-suited "salaryman" to don Aloha shirts and other casual wear as thermostats are being set higher in office buildings to conserve energy.

Nuclear energy provides a third of Japan's electricity. As measures to battle the power shortage, Tokyo buildings have toned down lighting, stores are closing sooner, and commuters are trudging up and down stairs instead of using escalators and elevators.

At homes, people are being encouraged to endure room temperatures of 28 degrees Celsius (82 degrees Fahrenheit), use fans instead of air conditioners and unplug personal computers and other gadgets.

Masataka Kunugimoto, auto analyst at Nomura Securities Co., said the plan to move weekday production to the weekend was a good one, and urged other sectors to do the same, but take other days of the week off.

"The number of companies in the auto industry is relatively few and so they could unite on the plan," he said. "It will definitely work as a plus for the electricity supply."

The expected power crunch is yet another challenge for Japanese automakers, which are all running at reduced output after the quake damaged some 500 parts suppliers in northeastern Japan.

Toyota Motor Corp. and Honda Motor Co. are not expecting to return to pre-disaster production levels until late this year, while Yokohama-based Nissan is targeting October.

Shiga said Japanese automakers are struggling against other challenges such as the surging yen, which reduces the value of exports, high taxes, pressures to reduce global warming and rivals at nations that have been quicker than Japan in forging free trade deals.

Auto production in Japan was already stagnating from a 20-year slowdown when the March 11 9.0 magnitude earthquake struck.

Auto production in March, totaling 404,039 vehicles, plunged 57 percent from the same month the previous year, marking the sixth straight month of declines.

But Shiga said Japanese manufacturing displayed power to recover after the disaster - starting to gradually return to normal production in barely a month. And he credited the "focused energy" of the people in northeastern Japan.

"There was drama. There were heroes," he said proudly.