Colm O&rsquo;Donoghue will retain the ride on Joshua Tree, the hot Aidan O&rsquo;Brien&#45;trained prospect for the $6.1 million Japan Cup at Tokyo on Sunday. The confirmation of O&rsquo;Donoghue as the rider for the Canadian International winner means that Johnny Murtagh has ridden his last race as contract rider for Coolmore. It also suggests that the O&rsquo;Donoghue could be the Murtagh&rsquo;s successor at Coolmore, especially as Christophe Soumillon has signed on as first string rider for Ecurie Wildenstein in France.O&rsquo;Donoghue has ridden Joshua Tree in both of his stakes race triumphs, having also partnered the Montjeu colt to win the one&#45;mile, Group 2 Royal Lodge Stakes at Ascot last fall. With only six lifetime starts under his belt, Joshua Tree is the one horse in the Japan Cup field from which further improvement is expected.&ldquo;He is very fresh and in good order,&rdquo; commented O&rsquo;Brien assistant Thomas Crawford.Half of the eight foreign raiders in the 1 1/2&#45;mile Japan Cup hail from France. Timos, the Thierry Domen&#45;trained son of Sholokhov who has been placed in two Group 2 contests going 1 1/2 miles in France this year, was the last to arrive on Sunday. The other three, Marinous, Cirrus des Aigles and Mores Wells, have all arrived at Tokyo Racecourse in good order, with Marinous&rsquo;s trainer Freddie Head scheduled to arrive on Thursday evening. Davy Bonilla will take his regular place aboard Marinous, a 4&#45;year&#45;old son of Numerous who won the Group 2 Grand Prix de Deauville before finishing sixth, six lengths behind Workforce, in the Prix de l&rsquo;Arc de Triomphe.That form doesn&rsquo;t look too promising for Marinous, as Nakayama Festa, the possible Japan Cup favorite, was second in the Arc, just a head behind Workforce. Trained by Yoshitaka Ninomiya, the 4&#45;year&#45;old Nakayama Festa, a son of Dubai Sheema Classic and Hong Kong Vase winner Stay Gold, returned from France on Oct. 6, three days after the Arc. He was no certainty to run in the Japan Cup but after a sharp Oct. 10 work, Ninomiya announced that he would run. &ldquo;He isn&rsquo;t the easiest horse to work with,&rdquo; the trainer said, &ldquo;but everyone at the stable deserves full credit for making him as strong as he is.&rdquo;Nakayama Festa beat his main local Japan Cup rival, Buena Vista, by a half length in the 1 3/8&#45;mile Takarazuka Kinen on June 27, but the very popular filly might be the post time favorite on Sunday. Buena Vista, a Hiroyoshi Matsuda&#45;trained daughter of 1999 Japan Cup winner Special Week, is coming off a win in the 1 1/4&#45;mile Autumn Tenno Sho at Tokyo on Oct. 31. She will be ridden by Soumillon, who rode her for the first time that day.