Behind the global success of Japanese video games lies a delicate task: appealing to overseas players whose expectations on issues such as sexism are increasingly influencing the content of major titles.

With the majority of sales for big games now outside Japan, everything from slang words to characters' costumes must be carefully considered for a global audience.

It is a complex process that has come a long way since the "Wild West" of the 1980s and '90s, according to one high-profile "localization" team.