Michelin rest: single guest possible?

I have a few days in Tokyo and was considering a more upscale dining location. Not that I am into Michelin star restaurants, but it described what I would like to find out pretty good.

Is is common or possible to have dinner alone in a Michelin (or otherwise great restaurant) star restaurant in Tokyo? I am not looking for the 3 star experience, but would I also need reservations for a 1 star place? Or should I perhaps consider lunch instead (just as fine), also to keep costs in control a bit?

I am mainly looking for a memorable place to have dinner. I am writing about the trip, and a good restaurant recommendation would fit perfectly within the publication.

Maybe you have some suggestions? I am staying near Shibuya, but I can pretty much go anywhere...

First thing first: Call to make a reservation (such a place most likely require a reservation). And when asked for how many, say one. Now days, solo dining is quite common, so I don't expect any issues. But a tiny restaurant might have a 2 person minimum policy simply because they need to fill every seat to make profit. I have encountered such restaurant only once, but I convinced the owner by telling him that I am a big time foodie and I eat and DRINK lots of expensive wine. And I did.

Just depends. Like mentioned above, small restaurant or high end Kaiseki places (that have only private rooms) sometimes have "reservation for two or more" policy, but most places would be ok.
You do need booking for 1 star restaurants month ahead. Many places start taking bookings on 1st of the month for the next month.

If you go for dinner you most certainly need reservations, and usually a month in advance. Lunch is different, you can table wait for lunch if you have the time in most places if it is available.
I've never had an issue with being a single dinner.
I'd recommend "The Oak Door" at the Park Hyatt in Roppongi Hills, the Kobe with a Chilean Cabb.

It doesn't matter if it has a 2 person policies, i've made reservation at a mid class Wagyu yakiniku BBQ place for one person, on their site, it does state certain meals are for two person or more, and reservation can only be made minimum 2 person.

But I got in as a solo, so it doesn't matter, just try it, worse case is you just get rejected.

Place I went to.

http://www.rokkasen.co.jp/en/contents/access.html

That kind of Yakiniku BBQ place would be no problem.
Because they have so many seating and not really a high-end place.

But if you are talking about 7-8 counter seat only kind of high-end, it's difficult no matter how many people- 1 or 2, doesn't matter, it's gonna be always hard to get in.
But yes, maybe lunch is easier. At reknowned Kyubei, you can most likely walk in after 12:30.