He thought he was being followed when he ran into the large store, where he believed he would be safe from the gang because there were so many people about.
It was believed gangs of foreign workers, from Brazil, had taken exception to foreign rugby players in the city, and had been targeting Collins.
Being put into police custody was a "relief", Collins told Campbell. He also wanted to reject speculation he was high on drugs at the time of his arrest. Witnessess said he was sweating, anxious and appeared disorientated but Collins maintains tests have shown no illegal drugs in his system.
Charges have not yet been laid against Collins, who is a 48-test All Black.
His arrest certificate states he was arrested for carrying a 17cm "houcho [kitchen/carving knife] in public 'without a valid reason', such as for work purposes."
If it is classed as a kitchen knife he could face up to two years in prison and a fine of 300,000 yen ($3796). If Collins was judged to be in possession of a sword he could face up to three years in prison or a fine of up to 500,000 yen ($6328).