Men -Wear dark suits (navy or black) with white shirt and subdued tie from October - April and gray suit from May - September. Japanese summers are hot and humid and most Japanese men wear half-sleeve shirts during the summer months. Japanese men typically have well groomed short hairstyles.
Do not wear black suit, white shirt and black tie because that is funeral attire. Japanese companies do not allow male employees to wear beards nor to shave their heads. Of course your attire is not complete without your Japanese business cards!