Hamamatsucho Transfer
 

On my last trip from Shinjuku to Haneda, I took the Oedo Line to Hamamatsucho station and tried to transfer to the Tokyo Monorail. At the IC gate, the terminal kept refusing my Suica card.

Is there any reason why I couldn’t transfer to the Tokyo Monorail? My Suica card had at least 2000 yen loaded.

I don't exactly know what your deal was, but the link between the Oedo Line and the Monorail isn't a transfer. You're basically exiting the Oedo Line station altogether and then entering the JR/Monorail area.

There is no relationship whatsoever between the two, and I don't even think you can buy a through ticket that you can exit the Oedo Line and enter the Monorail on the same ticket.

I don't remember the exact details (it was several years ago), but I recall a situation at some station or other where transfers had to go through a certain turnstile and not others, but the explanation was in Japanese only, which seemed inconsiderate.

The Hamamatsucho Station on the Oedo line MAY be one of those cases.

I just wish I could remember the details of that tricky transfer.

Both Pickles and ksandness are correct regarding my situation. Leaving the Oedo Line, I had to walk 5-10 minutes above ground to get to the JR station so it wasn’t a transfer.

This was the only station I had difficulty switching from one line to another.

Likely you have done is taking Oedo Line from Shinjuku to Daimon, then Hamamatsucho to Haneda Airport on Tokyo Monorail.

Likely scenario is that when you got off at Daimon station by some reason your Suica card did not register as you got off at Daimon station. Did you swipe your Suica card as you walked out of Daimon station? Not having record of getting off at Daimon station is likely reason your Suica card was not accepted at monorail Hamamatsucho station.

Also, traveling from Shinjuku to Haneda Airport more common routing is JR Yamanote Line from Shinjuku to Shinagawa, then Keikyu Line from Shinagawa to Haneda Airport.

On your routing using Suica was total fare of 699 yen, where JR Yamanote line and Keikyu Line routing using Suica is 601 yen. :)

If you have a phone with NFC, there is an app you can get that will let you see the history of the SUICA card. If you *really* want to know what happened, that's probably your best bet.