In the game Gallop Racer how do you open the Field of Legend

Though the field-of- legend mode is inaccessible from the start, putting in enough time with the title- collection mode will unlock this series of challenging dream races. This mode is strictly for the most dedicated players, since you need a stable of at least seven top-form horses to run right in the field-of- legend mode, where a single loss will take you out of the running