Yeah, Silver seren doesn't explain what source exactly he has in mind when he says the "topic" is "obviously notable".  
 I see a few dozen of hits in Ninja-boom literature, where this term is always presented as an item in a list. This doesn't make it a "topic". At the very most, it makes for a wiktionary entry.  

 Silver seren, if this is your approach to "research" for writing articles, I am not surprised we do not have a "Shinobi-iri" page that is worth the space it takes on the server's harddisk.