Hello guys !! I'm new in the world of japanese knives, and finally invested in 2 masakages for home use: A nakiri and a guyto. The guyto is from the shimo line of masakage, which is known to have a very reactive blade. I thought "no problem" because it's for home use and I'm used to care for carbon knives, before the masakages my go-to knife is a carbon sabatier, fact is.. the shimo is WAY more reactive than the sabs. And today it developed some sort of brown colouring, which I'm not sure if is rust or just patina. I've been cutting tomatoes, cherry tomatoes, red onions, lemon, potatoes and some fresh cheese. After cutting each ingredient, if I would not cut the next immediately, the knife was passed under water, dried with a cloth and left on the cutting board (that had moisture). See the pictures, what do you guys think?? PS: Sorry for bad english .. really not my native language..