Keepers Nursery do 4 varieties, the above three plus Twentieth Century. However they only have Kumoi remaining for the present season, and 20C is only available to special order.

Mike must have Kumoi if he is talking about frost protecting them to get them ripe. Shinseki and Shinsui are early ripening, my Shinseki ripens in August in a warm year, never later than mid september. Shinseki and 20C are not russet, but a translucent light yellow, very beautiful.

More to the point is that they are quite early flowerers, and you can lose your crop following a nasty frost in early april, as this year. Normal pears serve for cross-pollination, but you'll need an early one.