Top graft-buster Wang Qishan has made an unusually upbeat assessment of the anti-corruption campaign. "The working style of the [Communist] Party is improving, the spread of corruption is being contained," said Wang on Wednesday, when meeting Vietnam's Deputy Prime Minister Nguyen Xhan Phuc. "If we hold on consistently, we will have made an achievement in strict rule over the party." Wang has publicly shown little optimism since taking the helm at the Central Commission for Discipline Inspection in 2012. In January, Wang said the party's working style had improved but still risked a backlash. "The political ecology in some places is terrible … the mission to contain the spread of corruption is still an arduous one," he said. In October he was similarly downbeat: "We have stepped up the anti-graft campaign but some party cadres are still undeterred. Some have become even more corrupt," Wang said. Read more: Some cadres shrugging off anti-corruption campaign, graft-buster warns Wang has not held back even when meeting foreign guests. "The leadership headed by Xi Jinping has decided the anti-graft campaign faces a tough situation," he said when meeting Laotian President Choummaly Sayasone last July. "[We] must firmly contain the spread of corruption." Wang's change of attitude was a sign of increased confidence in the anti-corruption campaign, said Zhuang Deshui , at Peking University. "Wang didn't dare to say so before because he hadn't wrapped up the tigers at sub-national level and dismantled their networks," Zhuang said. "Now the leadership has firm control of the political situation …we might see fewer tigers on that level." Late July saw two top cadres from former president Hu Jintao's days, both at the sub-national level, expelled from the party - Hu's former aide Ling Jihua and Guo Boxiong, former vice-chairman of the Central Military Commission. "The focus [of the campaign] will be shifted from striking hard to a more comprehensive approach," Zhuang said. "We can expect some amendments of party regulations in the second half of the year." Wang Yukai, professor at the Chinese Academy of Governance, said the anti-graft chief's assessment was shared by others in the leadership. The anti-graft chief's comments, along with his recent discussion about the party's legitimacy, showed the party was undergoing political adjustments in the face of new challenges, said commentator Zhang Lifan . "The economic slowdown has posed a new challenge to the party's legitimacy," he said. "The party is still united about safeguarding its power despite internal struggles …We will see fewer tigers in the short term."