Ninin ga Shinobuden

These both have very similar styles of comedy with lots of sight gags and general silliness. They are also both very slice of life, with very little to no character development or ongoing plot to get in the way of the craziness. They're also both ecchi, but self aware of it. 

These anime both feature more cartoony art styles and have random sense of humors. Sure they have action moments here and there, but neither one are meant to be taken seriously and are just silly comedies. 

The perverted humor in both titles is present, as well as the craziness that ensues the title characters in both series. 

Both are comedy anime with no real plots. The episodes are very random. While Azumanga takes place in a normal school, Shinobuden takes place in a ninja school.  

Aside from the similar art styles, the shows also are broken up into short episodic stories, and have a very bizarre sense of humor. Both shows are extremely surreal, so unless you watched Shinobuden for the fanservice, you'll enjoy Tsukune-chan. 

When I first watched Hayate no Gotoku I felt a spiritual presence coming from 2x2 Shinobuden. Both are notorious for anime parodies. Not to mention that Shinobu and Hayate have some extreme bad luck (Shinobu with her ninja skills, Hayate with money). You’ll also hear a familiar voice that will remind you of Onsokumaru. Don’t forget the mascot thing (the white tiger and the crocodile). 

These two shows have a similar style of stupid and nonsensical humor where nothing is ever serious. They also both make light of ninjas and assassins. 

Both series are about kunoichi's aiming to be the best they can be. Despite the titles of the two series, all you will get throughout the majority of both animes are comedy and fanservice with little to no action slashing scenes. 

Both shows feature a clumsy, yet eager protagonist whose physical charms are exploited for the sake of the show's fanservice, and feature some yuri undertones as well. 

Both shows feature a good hearted yet ditzy protagonist as well as good dose of silly humor and fanservice. 

Both have similar characters(Natsumi and Koyuki=Kaede and Shinobu). Also they are both hilarious comedies and contain many parodies. Though "2x2=Shinobuden" is a little(or a lot) more PG-13. 

Both involve random comedy without any sort of real plot. Both have a female lead role surrounded by useless male characters. 

Himawari! is the more serious of the two, but it's still a comedy about a kunoichi in training. Watch Himawari! if you want more bite in the story. If you like ninja nonsense and shenanigans galore however, 2x2 Shinobuden is the one to watch. 

U all wont regret watch this anime :)...the storyline is very funny n all the episode is laughable...^^.there are some scene from terminator 3,if u notice... 

Both titles feature over the top fan service and comedy, if a weak storyline doesn't bother you. Then these two titles will keep you entertained all the way. 

Different themes and style (CGI and Drawn), but both deal with a lot of sarcastic, stupid, random and hilarious scenes. And that's the way they are similar, through their "stupid" humor. 

Although both are very different, they both deal with the same (huge) amount of humor, on the different ways etc. Tho' Animal Yokocho is more enjoyable. 

Just like the original himawari it and shinobuden it focuses on the life of an incompetent modern kunoichi with a lot of heart always making an idiot of herself. If you like shinobuden this is a little more plot but not much and really hilarious. 

You thought 2x2 was weird, meet FLCL, which takes it a step further. Over the top humor and energetic characters.