Toyota sees cost savings over $2.7 billion annually

"I don't want to divulge too much, because this is really a corporate secret," he said, but added that there was a hint in the 1/X concept car shown at the Tokyo Motor Show which weighs just 420 kg -- one-third of the Prius, with twice its fuel efficiency.

Toyota is the world's most valuable automaker, with a market capitalization of more than $200 billion. Its revenue reached $215 billion last business year as sales grew in North America, Europe and China, although Toyota is conspicuously behind in the budding Indian market.

Toyota has forecast sales of 9.34 million vehicles this year, including units Daihatsu Motor Co and Hino Motors Ltd, likely toppling General Motors Corp as the world's top seller of automobiles. Excluding GM's minority-held Chinese joint venture, Toyota ranked first in 2006.

By 2009, Toyota aims to expand sales to 10.4 million a year.

(Additional reporting by Aiko Hayashi and Nelson Graves)