Nishino was appointed after Vahid Halihodzic's sacking, despite leading the Blue Samarai to 2018 World Cup qualification.

In many ways, Halihodzic was sacked for trying to solve the same problems the 63-year-old now faces.

After taking an extremely inexperienced squad to last December's East Asian Cup, with the ideal of adding depth to a largely ageing squad, Halihodzic's youthful side suffered a 4-1 battering at the hands of South Korea and the Bosnian coach was gone.

Now, Nishino - a coach with no international experience - inherits the same problems, but with a lot less time to solve them before their opening World Cup match against Colombia.

"Through the process of trying it in tomorrow's match, I want to identify the best way to fight against Colombia, whether it is with three centre backs or four," Nishino told reporters on Tuesday.

"We need to choose the base formation and having (either) three or four at the back will be chosen to give us the most realistic chance of fighting Colombia."

"After fighting 100 percent in tomorrow's match and thinking about various things then I will need to choose the squad on the morning of the 31st," said Nishino.

"My suffering or worrying will continue."