Hello Artur,   Thank you for posting images and questions.   I am not sure that the yashadama is used for a dark brown coloration. Perhaps if the infusion is extremely concentrated the color may have a chance at being deeper on the wood. You might try boiling the liquid to evaporate more water. You might also use brief immersion times followed by drying periods that might open the pores again to accept more stain. Soaking any piece of wood for eight hours scares me.   Did you make a te