IMPHAL, Feb 2 — Four former Manipur chief ministers, W Nipamacha Singh, Rishang Keishing, Radhabinod Koijam and RK Dorendra Singh, are among the 368 candidates for the forthcoming two-phase Assembly elections on February 14 and 21, according to official sources here, reports PTI. While Nipamacha Singh (Manipur National Conference) is locked in a four-cornered contest in Wangoi Assembly constituency in Imphal West district with Congress nominee Sagolsem Achouba as main rival, senior Congress leader Keishing is among eight candidates in Phungyar constituency in Uhrul district. Political observers said Keishing was likely to have smooth sailing though his long-time rival, Stephen Angkang of Samata Party would do his best to defeat the Congress leader who had represented this constituency more than five times. They said Samata Party leader Koijam who is locked in a nine-cornered contest in the prestigious Thangmeiband constituency in Imphal West district, was likely to face a tough challenge from his long-time rival Binoy Nighthoujam of Federal Party of Manipur. Senior BJP leader Dorendra Singh is locked in a five-cornered contest in the prestigious Yaiskul constituency in Imphal with former revenue minister and Congress nominee E Kunjeswar as his main rival. Observers said Democratic People’s Party nominee Lt Col H Sarat would also put up a strong challenge to both the candidates.