[1] These "colour metals", virtually unknown outside Japan until the late 19th century, have achieved some popularity in craft circles in other parts of the world since then.
Although other patination agents can be used on these metals, some artisans prefer the rich colors achieved with traditional rokushō in the niiro process.
Because rokushō has a dramatically different effect on sterling silver than on the alloys typically fused to it in bi-metals, a common technique in art jewelry is to engrave through the alloy layer in a pattern to reveal the silver underneath prior to patination.
The formulae for rokushō are not published widely or freely, but passed on in the Japanese craft tradition.
Additionally, several different formulas have been proposed to replicate the traditional product for those who prefer to make their own: Rokusho is not used alone, but mixed with one or more other chemicals.