Japan Bullet Trains from Toyko to Kyoto.

I believe the problem may be that the EX app does not take US credit cards. You may find more information here:

https://www.japan-guide.com/e/e2018.html#ticket

I will say that buying tickets well in advance is considered very unusual in Japan. Most people just buy one shortly before the Shinkansen departs. If you are at the ticket counter, the agent will ask if you want the next departure, if it is 10 minutes or less, or the one after that. The trains are so frequent between Kyoto and Tokyo they do not fill up, but during Sakura (cherry blossom season) I believe reservations are mandatory.

As mentioned above it is cherry blossom festival so I'm wanting to buy ahead of time. I did post in a couple of places. I just recently joined a few Japan facebook groups so I'll ask there as well. Thanks for letting me know the price won't vary too much.

I don’t believe cherry blossom season is typically “sold out”. I traveled last year early cherry season your route. No problems getting a ticket just before departure. Perhaps some trains are more popular and more full, but there are many departures.

However, I do understand wanting everything set with ticket in hand. You should be able to get some help with the EX app from Tripadvisor. Many questions there and successful users. Perhaps people used Paypal? I have not used the app.

I meant ApplePay rather than PayPal in above post - I can't edit.

I need my morning coffee........

The ticket prices do not change at all. It is not like Europe train travel at all in terms of discounts for advance purchase.

You could very easily just buy your ticket at the JR counter at the airport when you arrive in Tokyo. Trains leave between the two cities every 10-15 minutes so no need to worry about making a specific train. If you’d like to reserve ahead of time, you can buy through klook. You will still need to pick up your actual ticket from the machines or counter when you get there though.

There may be in-US-only deals if you have any other tickets to buy, from the official website.

As far as I've read, the only periods without non-reserved seating on Nozomi (fastest) Shinkansen are the New Year, Golden Week (late-April/early-May), and Obon (early August). Sakura season is not on the list.

So I think you could get away with buying your tickets upon arrival in Japan. The machines take cash if your cc doesn't work - in fact, in my earlier visits 10+ years ago, they only took cash which was a bit of a shock given the ticket price.

It’s been 5 years but we walked up and bought tickets to Kyoto during cherry blossoms just before departure

You can just go to a machine or ticket counter if you are more comfortable with that to buy when you arrive. There are so many trains that you will be fine. We went and had JR Passes last summer. We got them when we arrived in Japan, didn't "book" anything, just used them when we got there. No need to "book" anything. We took our luggage too and all was fine. I do believe the JR Pass price went way up, so it may not be the best price. A direct ticket can be easily purchased at the station machines. There is an English button so you will know what you are looking at. Hope that helps. If it makes you feel better to have it on hand, just get it on your arrival day. We did this, but it really wasn't necessary. Enjoy your trip.