TOKYO, Sept. 12 (Xinhuanet) -- Japan's opposition parties failed to conjure up an approach that could topple Prime Minister Junichiro Koizumi in Sunday's general election, upstaged by Koizumi's so-called "magic" campaign strategy.

    Katsuya Okada, who heads the largest opposition Democratic Party of Japan (DPJ), tendered his resignation, saying on a NHK TV broadcast, "It's natural for leaders to take responsibility for failing to achieve the goal they set."

    During the election campaign, Okada repeatedly said he would quit if his party failed to take power.

    "I apologize to DPJ members and their supporters for failing tobe able to take power," Okada said on the broadcast.

    Okada admitted that his party's political power is still too weak to defeat the ruling coalition of Koizumi's Liberal Democratic Party (LDP), which has held power almost continuously in the Japanese postwar era, and the New Komeito party.

    But he did not elaborate on exactly when he will give up the post or how the party will pick a new leader.

    The DPJ, which held 175 of the 480 seats in the House of Representatives when Koizumi dissolved the lower house, suffered its first major setback since the party's establishment in 1998 by gaining only 104 seats so far in the election, while Koizumi's LDP won a majority of 283 seats.

    As for the Japanese Communist Party and the Social Democratic Party, it is unlikely they will boost their parliamentary strength, according to Kyodo News projections.

    "We failed to have our policies reach voters unaffiliated with any specific party," DPJ Acting Secretary General Yukio Edano said on a separate TV broadcast.

    With Koizumi refusing to allow those who voted against his postal privatization bills to run on the LDP ticket and fielding telegenic, high-profile political rookies in many single-seat constituencies, the opposition tried to take advantage of the LDP's internal conflict.

    But the battle between the new LDP candidates and the postal rebels, branded by Koizumi as party Old Guard, captured the electorate's attention and dominated TV shows, which resulted in asurge in public approval for the premier.

    Even some opposition candidates called the situation "Koizumi magic", while the DPJ complained in writing to media companies that the flood of news only highlighted the LDP and it sought "fair" coverage of the campaigning.

    Okada criticized Koizumi for what he termed blindly focusing onpostal reform while setting aside other crucial issues such as Japan's pension system, and strained diplomatic ties with China and South Korea. Enditem