Why was Shonen Jump called Shonen Jack in Bakuman Anime? Bakuman was able to get permission to use a number of titles such as One Piece, Naruto, Hunter x Hunter, etc. The creators of the manga also work for Jump. Many of the characters in Bakuman are based on real life mangakas, assistants and editors working in Bakuman. 

The number of times it is used is mind boggling and seem odd to me. To be honest while companies pay for product placement, Jump had the perfect opportunity to add its own in an in-house manga/anime?

So, why did Bakuman use Jack instead of Jump, when they could have used it seemingly quite easily?

For example: Gintama has no problem using Jump in its anime.

In the manga translation I read, the magazine was called Shonen Jump, but was changed to Jack in the anime.
Because the anime was broadcasted on NHK.
NHK, being a public TV channel in Japan, doesn't allow commercial advertising.

Much like the BBC, NHK is funded by a &quot;receiving fee&quot; by every Japanese household, with no commercial advertising and the maintenance of a position of strict political impartiality.
(Emphasis mine)

Their official domestic program standard (Japanese) (or, &quot;standard policy&quot;) states this:

Item 12 - Advertising

It's absolutely not allowed to broadcast in purpose of commercial advertising or self-advertisement marketing.
In the middle of the broadcast, when it's planned to include corporate name, personal name, occupation, firm name, or trade (brand) name, regardless if it's an essential component or unavoidable performance, they will be judged impartially and then given the decision on how to handle them.


The staffs, trying to avoid this case as best as they can, replaced some of the names with others:

Shueisha (publisher of Shonen Jump) → Yueisha
Jump (Shueisha's manga magazine brand) → Jack
SHOSETSU SUBARU (Shueisha's monthly light novel magazine) → SHOSETSU PLEIADES
Margaret (Shueisha's manga magazine) → Magnolia
Hashire! Daihatsu Tanto (Japanese-brand car) → Hirameki! Tanto-kun


Source: Japanese Wikipedia, Yahoo! Chiebukuro, ひなぴし - HatenaBlog
P.S. another mind-boggling thing is, One Piece and Naruto were left as is in Bakuman anime.