Tokyo Metro puzzle #4

Question

Yet another Tokyo Metro puzzle based on the map! Puzzles 1, 2, and 3 are avaliable.

Riddle:

From the western of the U
Along the airport line,
Go along until you hit
A shining water line.

Then head upon to the first
And turn around with glee,
Don't forget to go on to
The algae, algae line.

From there you go until you hit
Upon a certain Diet
And then along the Astoria line
Through 3 more stations plus.

Now which station are you at?

Answer 1

From the west of the U,  
Along the airport line,

The western airport line is the Keikyu line

Go along until you hit a shining water line,

The Mita line looks like water (This part is probably wrong)

Then head upon to the first

Go to Meguro (I 01)

And turn around with glee,
Don't forget to go onto the algae, algae line,

The Namboku line looks like algae and you can go on it when you turn around

Upon a certain Diet
And then along the Astoria line

The D is capitalized, D is the 4th letter in the alphabet so go to the Azabu-juban (N 04) station. Also the Oedo line almost looks like Zwift's Astoria Line 8 (Also a stretch)

Through 3 more stations plus

Go from Azabu-juban (E 22) to Kokuritsu-kyogijo (E 25)

Now, which station are you at?

You are at the Kokuritsu-kyogijo station

Answer 2

I don't know where to start exactly, but I tried to pick in along the second verse of the riddle. (So I understand my answer is either totally wrong or incomplete)

Go along until you hit

A shining water line.

Move along a line until you reach a station on the Tozai line.

Then head upon to the first

And turn around with glee,

Don't forget to go on to

The algae, algae line.

Along the Tozai line, move until you reach the Otemachi station. This is the answer from the first riddle ("Head upon to the first"). Now continue along the Chiyoda line, as this has a colour similar to algae.

From there you go until you hit

Upon a certain Diet

Some research shows that the National Diet Building is near Hibiya. So you follow the Chiyoda line until there.

And then along the Astoria line

Through 3 more stations plus.

The Astoria line bares the same colour code as the Ginza line. So from Hibiya you go to Ginza and then add 3 more stations to arrive at Mitsukoshimae.