Matz's Ruby Interpreter or Ruby MRI (also called CRuby) is the reference implementation of the Ruby programming language named after Ruby creator Yukihiro Matsumoto ("Matz"). Until the specification of the Ruby language in 2011, the MRI implementation was considered the de facto reference. The RubySpec project has created a large test suite that captures 1.8.6/1.8.7/1.9 behavior as a reference conformance tool.