Complex sentence: In 1993, after realising that Kanemaru's impending trial would provide ample ammunition for his critics, Ozawa made an unexpected move--he and Hata formed the splinter Japan Renewal Party, seriously destabilising the LDP, and eventually ending its 38 year dominance of Japanese politics.
Split into simpler sentences: In 1993, realizing that Kanemaru's impending trial would provide ample ammunition for his critics, Ozawa made an unexpected move. He and Hata formed the splinter Japan Renewal Party, seriously destabilising the LDP and eventually ending its 38 year dominance of Japanese politics.