 The scores for (re)doubled undertricks are such that after the first vulnerable undertrick, "n" vulnerable undertricks cost the same as "n+1" undertricks when not vulnerable; for example, four undertricks when doubled and not vulnerable cost 800 points (100+200+200+300), the same as three undertricks when doubled and vulnerable (200+300+300).In rubber bridge only, a bonus is awarded at the conclusion of the rubber as follows