dpkg-deb treats my architecture as amd64 instead of x86-64

I just created a simple .deb package (using this tutorial ). This is my control file:

Package: bla
Version: 1.0
Architecture: x86_64
Maintainer: bla
Description: bla

The Architecture I got from uname -m: x86_64, however, dpkg-deb broke due to _ being an invalid char, so I changed to - which worked but broke on the installation phase:

dpkg: error processing archive bla_x86_64.deb (--install):
 package architecture (x86-64) does not match system (amd64)

So I turned to use amd64 as my architecture, and voila! Now I just don't understand this mismatch in architectures between uname -m and dpkg...