SELECT AVG("Pieces") FROM table_50306 WHERE "Start" = '1941' AND "Release" > '2001'
What is the average number of pieces for boards that started in 1941 and were released after 2001?
CREATE TABLE table_50306 (
    "Release" real,
    "Start" text,
    "Pieces" real,
    "Board (inches)" text,
    "Board (cm)" text,
    "Type" text
)