SamuraiBlue
Captain
Most all RR commercial Trent engine's fan blades are built in Japan due to it's extreme weight and balance control.Not that Rolls Royce would desperately need IHI/ Japan expertise ( they don't. Most know that).
RR also has very little experience with CMC technology which Japan is the forerunner for this technology as well.
Japan is also a forerunner in metallurgy which is Key in developing cutting edge SCB.
RR needs Japanese technology more than Japan needs RR.