Ing Stones, popularised (invented?) by Ing Chang Ki, are common in Taiwan. They are plastic with a metal center to provide weight, and fairly thick (10mm?).
They come in special bowls with sockets for the stones; when all sockets are filled there are exactly 180 of each colour. This facilitates Ing Counting.
zinger: Ing stones are inexpensive. They are made of plastic with a metal weight inside to make them heavier - plastic alone is too light. The plastic is slippery, and the stones are thick (10mm), making them awkward to handle and place. Also they are ugly in my opinion. The only upside is low price; otherwise they are inferior to glass and yunzi in every way.
Ing stones do have a special bowl with slots which allows for quick verification that exactly 180 stones are present. This permits a certain counting method to be done a bit quicker, but I see no advantage to that. Besides, the screw and spring mechanism on the bowls breaks easily, and stones do get lost.
Hicham: I kinda like the Ing stones as they are thicker then the usual glass stones. There is nothing wrong with 10mm stones, my slate and shell set is 9.8 mm thick, but the problem with the Ing stones is that they are shaped a bit too round and symmetrical, which can make them feel a bit awkward. I also think that there are different kinds of plastics which are used, as I have seen quite a difference in one set from the other in feel and look.
The bowls are very useful, I would even go to say that they are a necessity if you play with Ing rules, which requires a complete set of stones. But the build quality is (very) poor, which can be very annoying.
Anonymous: After owning a set of Ing stones for a couple months I've had a problem with the metal inserts of quite a few of the stones losing adhesion to the plastic covering so that the metal insert is actually rattling around slightly inside the plastic covering. You can still use them of course, but it is kind of annoying. Has anyone else had this problem?
Anonymous:I have the Ing bowl and stones that match the picture Does anyone know if there are other styles available?
pwaldron: My understanding of the Ing stones and (particularly) bowls is that they have gone through many design changes over the years, but only one style is produced at any one time.
JoelRSimpson?: My club has several sets of these stones and everyone loves to play with them, but the plastic locking mechanisms (sliders) break easily during transport or when used. Does anyone know where to get replacement containers or even just metal latches?
Velobici: Having used Ing stones, boards and clocks (Ing Equipment) in AGA events for a number of years, I have developed a fondness for them. Not fond enough to buy them, but their appearance and touch remind me of all the AGA tournaments in which I have played and so are a well spring of good memories.
Joerg: Ing stones have one and only nice property. Unlike glass or quarz stones, they don't chip even with moderately rough handling. That's useful when transporting tournament equipment. They are decent to use otherwise, but not as nice as proper quarz stones.
ethnc: @JoelRSimpson?: our club has several of these trusty bowls and the clips broke off. If you have access to a 3D printer, I designed a replacement clip that works quite well. https://www.thingiverse.com/thing:4057547