How much do i need to

I dont intend to visit japan for tourism purposes, i plan to visit japan to find my dad, i just dont know where to start but i do plan to go to japan this coming april, i practically know what city he lives but from there nothing more. How much do i need to bring? Where do i need to go if i want to find him without disturbing his family, i just to keep it a secret. Sorry for the questions. I just feel a part of me is missing and i know if i dont do this i wouldnt be able to find myself.

You don't have to answer anything you don't want to: so you have your dad's full name, the city where he lives in, but you don't have his full address. Are you registered officially in his "koseki" (family register)? Have you ever been part of his household, meaning, recorded on his resident record?

If not, you will not be able to get any further information from official sources such as city hall. I don't know your circumstances, but it sounds like you need some assistance from a relative or any family member/family friend, or hire a private detective to look into the matter.