CLASSIC filly Kenbu is out of the International Bowl and local champion River Verdon has been officially barred from his end-of-season target, the Queen Mother's Cup. Kenbu's absence from the $3.5 million Bowl is another dent to the prestige of the showpiece International events later this month, following the defection of English Derby third Silver Wisp from the Cup. The French-trained Kenbu may well have started favourite for the 1,400-metre event on the strength of a third placing behind Hatoof in the English 1,000 guineas and excellent subsequent form. But Chantilly-based trainer Francois Boutin has informed the Jockey Club that the filly will not run in the April 14 race. She is understood to have run below par in her seasonal debut and not to be ready for the $4.5 million Cup. First European reserve, Silicon Bavaria, now steps into the breach. Also French-trained, Silicon Bavaria has substantial form but not along the Classic lines of Kenbu. Director of Racing, Philip Johnston, said yesterday: ''It is a pity as Kenbu would have been a most attractive runner. The form was first class and it would have been very high profile stuff for the race in Europe. ''The northern hemisphere challenge has been weakened slightly although Silicon Bavaria is a very useful type, too.'' But definitely on target for the Bowl is the Dermot Weld-trained Diamonds Galore. The eight-year-old gelding is well travelled but was reported earlier this week to have done a sparkling gallop at the Curragh. Diamonds Galore has run once this season, finishing an excellent second in a five furlong event at Leopardstown. In other International news, visiting Club Jockey Greg Childs will ride New Zealand challenger Romanee Conti in the Cup. Tony Cruz will be on American hope Cardmania in the Bowl. Trainer David Hill will now have to rethink River Verdon's local programme after the six-year-old was yesterday officially banned from running in the domestic Group Two Queen Mother's Cup at Sha Tin on May 29. The race is now restricted to horses rated 120 and below, preventing River Verdon from running over 2,450 metres for the first time - the trip that many observers think will see him run to his full potential. The decision is sure to be a huge disappointment of the two million-plus local race fans who would have been eager to see River Verdon run over the maximum trip, as well as to his connections. But handicapper T. W. Lam, while not specifically mentioning River Verdon in name, reasoned: ''We are keen to give the other horses and other owners a chance. There are other options such as the Champions & Chater Cup and the Stewards' Cup which are absolutely ideal for horses rated over 120.''