▁culture . ▁A ▁common ▁characteristic ▁of ▁these ▁( o ften ▁online ) ▁cases ▁is ▁the ▁avoid ance ▁of ▁hard - to - type ▁circum flex es ▁or ▁mac rons . ▁Also , ▁some ▁ambigu ities ▁in ▁sp elling ▁may ▁exist . ▁Sp ell ings ▁are ▁seen ▁that ▁would ▁fail ▁to ▁produce ▁the ▁desired ▁k ana ▁when ▁typed ▁on ▁a ▁computer , ▁for ▁example ▁failure ▁to ▁distinguish ▁between ▁ ▁( pro per ly ▁entered ▁as ▁" zu ") ▁and ▁ ▁( pro per ly ▁entered ▁as ▁" du "). ▁ ▁Sp elling ▁convent ions ▁ ▁In ▁practice , ▁there ▁are ▁as ▁many ▁variants ▁of ▁w ā p uro ▁r ō ma ji ▁as ▁there ▁are ▁manufact ur ers ▁of ▁word ▁processing ▁and ▁I ME ▁software . ▁Many ▁aspects ▁of ▁He p burn , ▁Kun rei ▁and ▁N ih on - sh iki ▁roman izations ▁are ▁accepted , ▁so ▁that ▁both ▁si ▁( K un rei / N ih on - sh iki ) ▁and ▁sh i ▁( H ep burn ) ▁resolve ▁to ▁. ▁Some ▁convent ions , ▁however , ▁differ ▁from ▁standard ▁roman izations : ▁ ▁O wing ▁to ▁the ▁difficulty ▁of ▁entering ▁dia crit ics ▁like ▁mac rons ▁or ▁circum flex es ▁with ▁standard ▁key boards ▁( as ▁well ▁as ▁the ▁ambigu ity ▁of ▁ ō , ▁etc ., ▁which ▁in ▁He p burn ▁can ▁represent ▁either ▁ ▁or ▁) ▁long ▁v ow els ▁are ▁almost ▁univers ally ▁entered ▁following ▁k ana ▁sp elling ▁rules ; ▁thus , ▁k ou ▁for ▁