In a 2L saucepan, combine soy sauce, sugar, sake and fresh ginger
slices. Bring to a boil, stirring until sugar is dissolved, then
boil until reduced to 1/3 cup. Discard ginger slices and keep sauce
warm. Rinse fish (which has been cut into 4 equal portions), pat dry
and brush lightly with oil. Place fish on grill about 6 inches above
a solid bed of hot coals. Cook, turning once, just until browned on
outside but still pale pink in center; cut to test (3-4 minutes). To
serve, place each piece of fish on a plate. Arrange 3 papaya slices
each piece of fish; then top each serving equally with soy-ginger
sauce and candied ginger. Garnish with julienned bell peppers.