The birthday is easy to know, but time is difficult. In chinese , birth time is defined within two hours. It means, in a day of 24hours, yesterday's 23:00-today's 1:00(2hr, chinese call it  as mouse ), 1:00-3:00(2hr, cattle),3:00-5:00(2hr,tiger), like this, totally 12 kinds. So you must know time duration