Japanese promos for music and some anime have recently gotten less available than they used to be on YouTube as previously accessible official video uploads from major content providers have started showing up blocked with the message "is not available in your country." 

The common culprit pointed to in much of the conjecture and buzz is the concerns around the upcoming launch of the YouTube RED paid subscription service. There's a region aspect to the speculation, since the $9.99 a month service will first be rolled out in America, and a rights dimension, with companies like ESPN already backing off from being involved with the series.

In terms of what's no longer available,

Arama! Japan lists

Victor Entertainment (and channels by acts under them like Sakanaction, Southern All Stars, Hoshino Gen, and Leo Ieiri)

Columbia Music Japan (and channels by acts under them like TRUSTRICK, clammbon, and Not yet)

Up-Front (and channels by acts under them like Morning Musume, Juice=Juice, LoVendoЯ, and C-ute)

AKB48

SKE48

HKT48

NGT48

Pony Canyon (and channels by acts under them like aiko, w-inds., Katahira Rina, and cinema staff)

Teichiku (and channels by acts under them like Sayuri Ishikawa and X4)

dreamusic

P-VINE

Zankyo Record

UK.PROJECT

tricot

sputniklab

Yonezu Kenshi

Ling Tosite Sigure

Yasuda Rei

LEGO BIG MORL

Stardust

Yamaha

Flower

Alice Project

SCANDAL

The GazettE

Flying Dog (and channels by acts under like Maaya Sakamoto)

Being (and channels by acts under like B’z, Mai Kuraki, Meiri Alaha, and BREAKERZ)

VocaloidOtaku lists

Producers:

U/M/A/A (DECO*27, Sasakure.UK, Powapowa-P)
08yakari (Hachi)
Incstoenterinc (Supercell, Yuuyu)
Being, Inc. (Doriko)
EXIT TUNES (Dixie Flatline, Heisei Project,CosMo/Bousou-P)
Elicense (Nem)

Songs:
Spoiler Hide
Popipo (Lamaze)
Yellow (kz/livetune)
Jitter Doll (cover by kyaami)

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Scott Green is editor and reporter for anime and manga at geek entertainment site Ain't It Cool News. Follow him on Twitter at @aicnanime.