There is indeed very little information about this online.
A question asked prior to 2003 on the site 'www.h2.dion.ne.jp' (no longer online): Q: Do shinkansen trains have power outlet sockets for running laptopcomputers?
A:
Generally, no, although the latest 700 series trainsrunning on JR West Hikari Rail Star services do have power outletsockets.
Wikipedia confirms that the most 700 series models have power outlets for passengers.
Hikari 546 is a N700 which have power outlets.
Hikari 470 is a 700 which most likely have power outlets.
Max Toki 329 seems to be an E4 series which is not likely to havepower outlets.
Only the N700 trains between Tokyo and Osaka have Wifi, and you still have to pay for it before you board the train using one of the Japanese carriers like Wi2 or Hotspot
travel.stackexchange.com/users/1317/Peter Hahndorf
I can verify that the N700a trains have power sockets for the seats at the ends of the cars.
Look at the bottom of the side wall under the window near your feet.
Plugged in right now, actually :-)
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The E5 and E6 series used in northern Japan (Tohoku Shinkansen; Komachi, Hayabusa, some Hayate) have a pair of 100V outlets for the front row of each car, and a single outlet beneath the window on the other rows on each side.
Note that since the seats rotate, there are also two outlets behind the back row of each car, although they would be inconvenient to access.
travel.stackexchange.com/users/29672/Kent
For online resources, this Japanese page has a list.
The train names might survive Google or other machine-translations.
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Sitting on a Kodama now and can't find any unfortunately, for future reference.
travel.stackexchange.com/users/43737/David
Do the Shinkansen trains have wifi? How about electrical plugs?  If it depends on the train, these are the ones I'll be taking:   Hikari 546 (Hiroshima->Shin-Kobe)  Hikari 470 (Shin-Kobe->Tokyo)  Max Toki 329 (Tokyo<->Niigata)   I'd also accept as an answer an online resource where I can look all this up (I failed to find one on my own).
Are there electrical plugs and/or wifi in Japanese shinkansen?
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<japan><high-speed-rail><wifi><power><electronic-items>
travel.stackexchange.com/questions/4894
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The 700 series models, including the Hikari 470 and 546, have power outlets for the seats at the end of the cars. The E5 and E6 series used in northern Japan have a pair of 100V outlets for the front row of each car, and a single outlet beneath the window on the other rows on each side. N700 trains between Tokyo and Osaka are the only ones with Wifi, which you have to pay for before boarding. Kodama trains do not seem to have sockets. A number of Japanese trains have power outlets for passenger use. However, the Kodama train does not. WiFi is only available on the N700 trains from Tokyo to Osaka and it is a paid service.
A number of models of Japanese train have power outlets for passenger use, including N700 and the E4, E5 and E6 series. Only N700 trains from Tokyo to Osaka have WiFi and you have to pay for it. The Kodama train definitely does not have power outlets.