There is another type of source for these cups - officially given cups. These are cups that are given to individuals from the Japanese government for various reasons, and usually in lieu of some other kind of decoration. Most common among these are cups given for various kinds of charitable donations, including donations to the government for war efforts and other kinds of civilian support for any military action. For example, in a book of all documents about awards, medals, and orders from the Decorations Bureau, which oversees all grants of orders, medals, etc, there is a whole chapter devoted to the gifting of cups and other monetary awards for meritorious service to the government.
The general hierarchy of cups is that the highest honors are a set of 3 stacking gold cups, then a single gold cup, then 3 silver cups, then a single gold cup. Finally there are the 3 stacking lacquer cups and single lacquer cups. No mention here, at least among the sections I've read, that talk about ceramic cups.
There are different styles too. The most basic ones are either with a kiri or a chrysanthemum. The kiri ones seem to be of a lower rank than chrysanthemum crest ones. For example, this cup
It has the 16 petals chrysanthemum crest on it. This crest is special - it is the imperial family's emblem, and cannot be used willy-nilly by civilians. Only official bodies can stamp this on items, which means this cup was given by the government to an individual in the name of the emperor. The kiri crest with the 5, 7, and 5 leaves arrangement is also a symbol of the imperial house but it's less restricted in use, from what I understand. Anything with the 16 petal chrysanthemum crest is therefore somewhat more special than others.
There are also other official cups but perhaps not given, strictly speaking, from the emperor. For example, this set:
It doesn't carry the name of the emperor or the symbols of the imperial house. Instead, it is granted from the Minister of the Army for some kind of merit - perhaps again a civilian who is connected to the military for the war effort, in this case WW1. Official cups of this sort are granted for all kinds of reasons, from garden parties to official rewards for military suppliers. These items also uncover aspects of Japan's military history in a way that is rarely seen in other places because of the physical embodiment of these services in the form of reward cups.