TOKYO, Sept. 22 (Xinhua) -- Japan's ruling Liberal Democratic Party (LDP) officially launched its leadership election campaign on Monday, with five candidates expected to register their bids.

The contenders are Agriculture Minister Shinjiro Koizumi, former Economic Security Ministers Takayuki Kobayashi and Sanae Takaichi, Chief Cabinet Secretary Yoshimasa Hayashi, and former LDP Secretary-General Toshimitsu Motegi.

All five also ran in last year's election, which saw a record nine candidates.