@user5924704 , that new bit of info changes everything.
(a) You made a presentation in country A, an US entity paid an award to you for this, you being a citizen of Japan.
(b) Because Japan is taxing you on world income, you have to recognize this income on your Japan tax return
(c) Depending on tax treaty etc. between country A and Japan, there may or may not be foreign tax credit eligibility
(c) Since the presentation was in country A, the award is NOT US sourced -- presentation / work is foreign ( for US purposes; it is not connected to US business that you own. This is an expense item for the US entity.
Bottom line you do not have to file a 1040-NR.
Arrigato
pk
