Japan is one of four possible runners for Aidan O'Brien in the Betfred Derby Trial at Lingfield on Saturday.
The Ballydoyle handler has saddled four previous winners of the Listed contest and looks set to launch a strong challenge once more.
Having rounded off his juvenile campaign with victory in the Beresford Stakes at Naas, Japan is disputing favouritism with some bookmakers for the Investec Derby at Epsom next month.
O'Brien could also call on Dewhurst third Anthony Van Dyck, South Pacific and Western Australia.
Ed Walker has entered Cap Francais, who was only narrowly beaten by O'Brien's Cape Of Good Hope in the Blue Riband Trial at Epsom on his seasonal reappearance last month.
Other contenders among the 17 entries include the William Haggas-trained Pablo Escobarr, Roger Varian's Three Comets, Mark Johnston's pair of Themaxwecan and Living Legend and Almania from Sir Michael Stoute's yard.
The Betfred Mobile Oaks Trial is a similarly intriguing affair with 13 fillies in the mix.
O'Brien looks set to rely on Zagitova, who was fourth in a Guineas trial at Leopardstown on her first start of the campaign.
The home team includes Haggas-trained Frankel filly Frakellina, the unbeaten Manuela De Vega for Ralph Beckett and John Gosden's trio of Frisella, Anapurna and Elisheba.
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