Welcome to FlyerTalk.
Pachinko parlors are ubiquitous, and I doubt you'll have much of a problem finding one.
I'll retitle the thread so members can see what it is about and may be more likely to respond- our TOS suggest:
Create Descriptive Titles - link to this guideline
Make thread titles as specific and descriptive as possible. Sometimes posters will start a thread with a very general title such as, "Guess what?" or "Strange airline policy". Be as helpful as possible in your thread titles, and if you want to improve or change your thread's title after you create it, ask a moderator in that forum for help.
Also be sure to check the japan-guide.com website out -
this link takes you to the Kanto regionsection, which includes Tokyo and environs, and
this link to Tokyo itself.