ICHIRO Ozawa, the politician widely seen as the key political strategist behind the present coalition Government of Japan, has given a clear indication of some of the major changes that will follow as a result of the political reform bills recently passed by the Japanese parliament. Mr Ozawa, who is the co-leader of the Japan Renewal Party, indicated the radical developments to come in an interview to the largest circulation Japanese newspaper, Yomiuri Shimbun. First, Mr Ozawa asserted that the present coalition of seven political parties would have to integrate into one party before the next general election. Second, he made it very clear that the new political party would be led by the present coalition Prime Minister, Morihiro Hosokawa. ''We should call on all parties, and people who want Prime Minister Hosokawa as their captain, to come together,'' Mr Ozawa told Yomiuri. The first development naturally follows from the key political reforms under which 300 single-seat electoral constituencies will replace 130 multi-member seats in the next election, provided enabling bills confirming the reforms are soon passed in the present parliamentary session. The surprise element in Mr Ozawa's interview is that he clearly prefers that the coalition changes itself into a single, unified party. But the choice of Mr Hosokawa as the new party's leader is no surprise given the high poll ratings and personal popularity which the Prime Minister has achieved in the past six months. Third, Mr Ozawa clearly indicated his belief that the coming changes in Japanese politics will involve the break-up of the Liberal Democratic Party and the Japanese Socialist Party. Lastly, Mr Ozawa wants the new political party to be united on basic political principles right from the start, including agreement on the issue of international security and deregulation of the Japanese economy.