China-Japan ties are at their worst situation in the past four decades, but the two countries cannot be against each other and must improve relations, a senior Japanese political figure said Saturday.

Koichi Kato, president of Japan-China Friendship Association and a senior expert on Japan-China relations, made the remarks on the sidelines of the 9th Beijing-Tokyo Forum that convened Saturday in Beijing.

The forum, held once a year since 2005, has gathered together hundreds of intellectuals, businessmen and politicians from both countries to share ideas on bilateral ties.

It is one of the few large-scale activities co-hosted by the two countries this year since relations between them have been hit hard by their territorial dispute ignited in September 2012.

Taking questions from China Daily, Kato said the fact that more than 600 people participated in the forum has "impressed" him and gives him "confidence" on the future development of bilateral ties, as it presents a larger scale compared with that of the previous years.

"Many participants are not diplomats, but students studying Japanese culture, Japan-China relations. That means they are worried about this. And they are ready for the improvement. So this symbolizes the possibility of the Japan-China relationship to improve," Kato said.

According to Kato, younger generation Japanese are also interested in China relations, but they are easily interested in the mass media that write about the Japan-China relationship.

The 74-year-old Kato now is still filling his schedule with bilateral communication and striving to work for the improvement of the stalled ties.

"Japan and China should not, cannot, and will not be against each other. So you have to improve relations," Kato said.

"Our two countries should never wage a war. Therefore the only path ahead of us is to improve the relationship," he said.

But Kato said he shared the views with many other people that the current situation is the worst of the past 40 years.

"It has been difficult," said Kato.