Once the golden boy of the Japan side, the 30-year-old is poised to play in his third World Cup this year and believes the current Japan side is the best he has played in.
"The quality of players and the communication is better," Inamoto told Reuters on Tuesday. "The coach (Takeshi Okada) has the team playing good football. The level has improved."
Japan have been drawn in Group E alongside Cameroon, Netherlands and Denmark and Inamoto vowed the Blue Samurai would be a tougher nut to crack this time round.
"The first game (against Cameroon on June 14) will be key," said the former Arsenal and Galatasaray midfielder before Japan's World Cup warm-up against Serbia in Osaka on Wednesday.
"We have to get a result. But even if we lose we must make sure we don't lose the plot like we did last time after we lost to Australia in our first game."
Japan exited the 2006 tournament with barely a whimper following their 3-1 defeat by the Socceroos as players bickered among themselves throughout the competition.
"If we do lose our opening game we have to keep our motivation and focus sharp for the next one," said Inamoto, who helped Japan reach the last 16 as 2002 World Cup co-hosts.
"We have to battle for three games and make sure we get through the group," added Inamoto.
Japan have never won a World Cup match on foreign soil and Inamoto said they could not afford to give teams a head-start in South Africa.
"We have to be very careful not to concede first," Inamoto said. "The top sides defend so well and are physically stronger than Japan.
"We could be in trouble if we go a goal down. We have to make sure we score first."
