Here is a lieutenant frock navy set I have. I didn't have the bicorne hat pictured, but I do have it. Sword is there, can kind of see it.

 

Beautiful frock coat and very complete! Violet belt piping for engineers?

Nice coat. Rich A. in Pa.

Beautiful frock coat and very complete! Violet belt piping for engineers?

That is right Matt, Violet for the Engineer Department, source, Andrew Mollo's 1975 Macmillan color series book, Naval, Marine and Air Force Uniforms of World War II.

That is right Matt, Violet for the Engineer Department, source, Andrew Mollo's 1975 Macmillan color series book, Naval, Marine and Air Force Uniforms of World War II.

 

I've been studying up on the IJN, the Naval Historical Foundation did an article about piping on collar tabs: https://www.navyhistory.org/2015/04/ditty-bag-imperial-japanese-navy-collar-tabs/

I wasn't aware they used the colored piping on dress belts before seeing this one. Very elegant uniform!

Thanks RRA, Matt, and Patches. Great link Matt. Never seen a few of the other colors before. I have seen the red, white, purple, and standard line officer belts so far. I have seen a green piped IJN peaked officer visor too.

As I understand, the use of colored piping on the visor caps was short-lived?

No idea.. but maybe so.. since they are very rare to find.

Daniel Griffin has a couple of examples of rare colored-piping IJN visor caps on his site: http://griffinmilitaria.com/cgi-bin/imcart/display.cgi?cat=9

According to the information I have, the color piping worn on officers and midshipman's service visor hats only was a limited program for men who were referred to as "special service officers". The program doesn't appear to have been well thought out and was abolished after about a year in the early 1940's.There were only 2 colors worn....purple (engineering) and white (accounting) on the service hats likely due to the shortage of officers in these specialized fields. Men were brought up from the enlisted ranks to fill these positions hence the name "special service officers". The size of the striping on the officer's shoulder boards also reflects this position. The color piping was never worn on enlisted hats. These same colors were worn on officers dress belts as well as their shoulder boards and collar insignia and conform with the colors of the metal cherry blossoms on post November 1942 enlisted sleeve insignia. Late in the war an additional "brown" cherry blossom was added. However, I have not seen brown on the officers belts or other rank insignia but have seen green, white, purple, red and royal blue so I would assume there must have been a light blue (aviation) piping on the dress belt also.