"All four horses have a pretty good chance. One is already a group one winner and World Ace ran fourth in Hong Kong in his last start.
"The other two horses have run second in group ones so they are quality horses and very competitive."
Ichikawa said the work rate would be increased in the coming days.
All four have come to Australia with good performances at their most recent starts in December.
To The World finished second to champion mare Gentildonna in the Arima Kinen, while World Ace finished fourth in the Hong Kong Mile.
Real Impact is a last-start winner of the group two Hanshin Cup, while Tosen Stardom won the group three Challenge Cup.
Although the four have been in Sydney since last Thursday, the quarantine clock starts again with the arrival of Hong Kong's Dominant.
The John Moore-trained horse joined them yesterday, meaning it will be another two weeks before they are officially cleared.
World Ace and Royal Impact will both run on March 21 at Rosehill in the George Ryder Stakes (1500m).
Tosen Stardom will run in the Ranvet Stakes (2000m) on the same day, while To The World runs a week later in the BMW.
Dominant, To The World and Tosen Stardom are headed to the Queen Elizabeth Stakes on April 11, while the target for World Ace and Real Impact is the Doncaster Mile a week earlier.