Asian Cast Iron Tray ?

I want to say the large tray is an ash tray (has ash residue in it ) because of the two ends with slots , not sure what the two square pieces would be for or if they belong with the larger tray ; the patina does not match and the green paint is different . Large tray is 12" by 6" , has some gold wash over the caligraphy in center and a stamp mark on backside (hard to photograph) . The two smaller square trays have coin impressions on the inside and caligraphy on the backs , they are 3" by 3" and are cold painted green (brighter green then the large tray) , again not sure these belong with the larger tray.
I have seen a few trays very similar to the large tray , referred to as Nambu Tekki ; none of them had the square trays with it as sets. The squares make me think Coasters for cups ?Incense burner or ash tray for the larger tray? Help with writing please and intended use of trays ? Any information appreciated .