How did the italians take over the numbers rackets

In places like Cleveland , Chicago , Harlem , Kansas city , etc etc how did the italians take over the numbers rackets from the Afro Americans so easily back in the 20's,30's,40's and 50's? I was watching an interview with Quincy Jones about his childhood. He had said that his father built houses for black gangsters in the 30's and 40's until the italians took over the numbers racket's and ran them out of the city. Quincy Jones grew up in Chicago btw

http://www.americanmafia.com/Feature_Articles_478.html

I don't know one Policy game today that is run by Italians. It's all Spanish. At least where I live. And the biggest are the in the local bars. Brazen too. Lot of places ( if you're a regular ) will assign you a number and you have to sign the book everyday. Rarely do you get odds either. Just a buck to take your chances.

In Chicago,Giancana kidnapped or killed the numbers racket kings.After some time the Chi outfit got out of the numbers racket,just took their cut

During the 40s the mafia fought and began taking over black numbers rackets and then held it during the 50s- early 60s and then towards the late 60s and into the 70s high crime rates, robberies and a newer breed of black gangsters(barnes, matthews) made it unsafe for white gangster to be operating in black areas diminishing the mafias prescence in those areas.

https://www.maryferrell.org/mffweb/archive/viewer/showDoc.do?mode=searchResult&absPageId=973825

FBI report detailing the trouble lcn was having with black criminal elements in newark new jersey.

I would imagine they did it with guns and violence, and did it easily because the world was theirs back then!!

Also, there were a few cities that withstood the takeover which I recall Detroit being one of them.

I dont think detroit was one of them. Italians basically overtook all the other ethnicities jews, irish, blacks anywhere there was a crimefamily anyway. To black gangsters credit it took italians longer to take over african american criminal activities and also they weren't able to keep control of it unlike the jewish and irish racketeers who sort of merged in with them as associates.