Faucet Connection

Both bottle washers and many types of wort chillers are designed to be attached to a water supply. And they come with the fittings appropriate for their locality, the US and Canada in many cases. In Japan, threaded plumbing fittings are quite different, and US-to-Japanese plumbing converters are not readily available. Much more reliable is to connect using tubes, barbed hose fittings and hose clamps.

A home-improvement store, for example J-Mart, has parts to accomodate standard household plumbing fixtures. Examples of pipe sizes used in Japanese plumbing are G1/2, M23x1.5 and W23山14. That isn't a typo, the pipe size actually is W26-yama-20, where yama is the mountain kanji. The 16 mm inside diameter garden hose is common, and few other hose sizes are available. For specialized parts, it a great store is Tokyu Hands, which has a good selection and helpful staff.

Fermtech Double Blast Bottle Washer

The Fermtech Double Blast Bottle Washer connects using a hose, rather than by screwing directly onto the faucet. The 3/8-inch hose has an adapter so it can be attached to a US laundry-machine or garden hose faucet, but this size is not used in Japan. Here are three means to connecting it to a common kitchen and bath fixture, where the swinging faucet attaches with a W26山20 fitting.

The first method uses two adapters available at Tokyu hands:

1. Cut off the end of the hose which has the original adapter on it.
   
2. Attach a 10.5 mm barbed hose-to-G1/2 female pipe thread adapter to the hose. 3/8 inch is 9.5 mm, and the barbed hose adapter is a millimeter bigger for a snug fit.
   
3. Attach this to a male G1/2-to-female W26山20 adapter.
   
4. Remove the swinging W26山20 faucet and attach to the the hose-and-adapter assembly.
   

A second method which might work is to buy a W26山20-to-15 mm garden hose adapter for the faucet, and a short length of 15 mm hose. Then order a 5/8-inch barbed hose-to-3/8-inch barbed hose adapter (also called a reducer or reduction fitting). A good source of such things is McMaster-Carr. Then, cut off the quick-release adpater that came with the hose, plug in the 3/8-inch end of the adapter. Use a short length of 15 mm hose to connect the other end of the barbed hose adapter to the barbed faucet adapter.
http://www.mcmaster.com/

A third method is described on the web site of Advanced Homebrewing that sells this bottle washer in Japan, although it was listed as being sold out as of this writing. As I understand it, the suggestion is to clamp a usual garden hose (15 mm inside diameter) to the outside of the bottle washer hose (outside diameter of about 13 mm). They expect that you'll be able to cut the old adapter, made of plastic, leaving the core inside the hose to act as mechanical support for a hose clamp. To connect it to the faucet, use a W26山20-to-barbed 15 mm hose adapter, which should be widely available. This is cheaper, but less elegant, than the first method.
http://www.amy.hi-ho.ne.jp/brew/equipment.html