This is as much detail as I can remember right now. (Some of the other regulars might add or correct bits of this).

(1) Can you drag your luggage on an escalator or must you use the elevators?
In my experience, the escalators are quicker - and it is possible to make this transfer in 15 minutes. So here are my instructions for doing that

(2) It might be a good idea to buy Green Car Tickets for the N'EX and the Shinkansen trip, since the Green Cars are located at the center of the trains -saves you from running from the far end of the platform and gives you fewer people to fight your way through - and a nice comfy seat after this sprint through Tokyo station

(3) Get your bags off the luggage rack and wait by the door before get to Tokyo

(4) Your N'EX train pulls into Basement Level 5 at Tokyo Station
Run to the nearest escalators and go up (there's no other way)

(5) You emerge on a rather empty floor - Basement Level 4

(6) See a bank of several long escalators moving upwards
(It may be in front or behind you - likely moving in the opposite direction to the escalator you just got off)
Turn 180 degrees and get on .... quickly

(7) Now you're in a bright area with retail etc. - Basement Level 1
Look around for a passage leading off to some escalators going up
There should be two escalators going up and two coming down on either side of a wide staircase
The direction will be roughly perpendicular to the way you were going so far
(It may be to your right or left - depending on which escalators you took)
Run to those escalators (past the shop of gaudy knick-naks for teenage girls)


If you don't see it, you might want to ask "Shinkansen wa doko deska?"

(8) As you are travelling up the escalator you can look behind you and admire the huge stained glass window ... reassurance that you're on the right track.

(9) You emerge at Ground Level a,k.a. Floor 1

Stop admiring that stained glass - face forwards, because you need to push through the crowds. Aim in a kind of diagonally forward and rightwards direction.

(10) You see a long, wide passage that runs the entire width of the station.
In the middle of the passage - souvenir shops selling cakes and cookies etc.
On either side of this passage are dozens of escalators going up to platforms. Ignore them

The first escalator you pass will have orange hand rails ... the next one will be green... or maybe blue.... keep running.

. This is the gauntlet you must run to reach the Shinkansen part of the station.... Leave that stained glass window behind you ...

(11) At the end of that passage you will see a small ramp and a few steps
Go up.

(12) Now you are in the Shinkansen area of the station
Yay!

(13) Look for the GREEN Shinkansen signs
Those GREEN signs will say Tohoku, Yamagata, Akita, Joetsu & Nagano Shinkansen

(Ignore the blue Shinkansen signs - which are for trains to the West of Japan).

(14) You will need to put your tickets into the large Shinkansen ticket gate.
If you find that the gate rejects your tickets, it mighh be because you have put your N'EX seat reservation ticket in there ... just show the tickets to a member of staff and ask them to put the correct ones into the gate.

(15) Look up at the signs above your head to see which platform your train is leaving from.

(16) The escalators are labeled with numbers - the platform numbers
Take the correct one to your Shinkansen platform

(17) Take a quick look at the sign above the platform before you get onto the train - just to make sure it's the right one.

(18) Drop your bags behind the back of the last seat in the carriage. Find your seat and sit back until you have the energy to go looking for the buffet car where you can pick up an ice cold beer.

... hope this helps.

BTW - Even if you miss your Shinkansen to Akita, you could still get the next one to Morioka, spend the night there and catch the first train in the morning to Akita. (If you leave Morioka at 7.58am you will be in Akita by 9.30am).