U.S. Government WW2 produced Information posters for both German and Japanese forces. Some of the information on these was inaccurate at the time.
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Below, German WW2 Luftwaffe Insignia chart amd U.S. Published Japanese Army ranks chart









Bottom row, German published charts for Heer ranks and a pre- war guide to the German customs service (Zoll)
Above Left, Post war Heer Rank Insignia chart                                                                                                         Above right, German pre-war uniform & Rank Insignia chart for the Zoll (Customs)