Rubuta ci gaba don wannan sakin layi - PURPLE ya kasance mai jan hankali, amma an iyakance shi sosai, taga cikin shirin Japan da manufofinsa saboda yanayin musamman na tsara manufofin Japan kafin Yaƙin (duba sama). Tun da farko, mafi kyawun taga dabarun ita ce Dokar Jirgin Ruwa na Japan (wani cipher mai ɓoyewa), wanda ake kira JN-25 ta masu binciken cryptanalysts na Amurka. Rushewa cikin sigar da ake amfani da ita a cikin watanni bayan Disamba 7, 1941 ya ba da isasshen bayani don haifar da nasarar sojojin ruwa na Amurka a cikin yaƙe-yaƙe na Tekun Coral
da kuma Midway, dakatar da farko Japan ci gaba zuwa kudu da kuma kawar da girma na Japan sojan ruwa iska ikon. Daga baya, zirga-zirgar JN-25 da aka rushe ya kuma ba da jadawalin da kuma hanyar jirgin sama Admiral Isoroku Yamamoto zai tashi a yayin ziyarar dubawa a kudu maso yammacin Pacific, yana ba wa matukan jirgi na USAAF damar kwantar da jami'in da ya yi tunanin kai harin Pearl Harbor. Kuma har yanzu daga baya, samun damar sakonnin sojojin Japan daga ɓarnatar da zirga-zirgar sadarwar Sojojin ya taimaka wajen tsara kamfen din tsibirin tsibirin zuwa Philippines da kuma bayan.