Undercutting

[Risvertasashi]

Yeah I have no idea how he did it, he must have seen me crafting a ton of them. But he messaged me something along the lines of "I know this may be weird but are you the jerk ruining the market?"

Even at 20k I was still nearly doubling my profit on each item, so it worked out in the end haha.

Items you craft have your signature on them.

It's not a surefire way to find out who owns a retainer as people can relist others' items if they decide they don't need them or to try to control the market. But that's almost certainly how you were found out - the item signature.