Look in the phone directory (or online) and find the nearest railroad maintenance yard. They will be glad to give you a piece of old track. It might be an hours drive, but worth it. Other good anvils can be made from a section of rail car axle set upright in concrete. That is called a post anvil, and is actually a good type for knife forging.
As said, scrap yards are a knife makers paradise. All kinds of things will make an anvil. If it is mild steel (say a 400 pound piece of 24X12 I-beam) order a block of steel (anything from 1050 to 5160), about 3X6X2", and harden it.Draw a 500-600F temper. Then weld it to the top. You will have a workable Japanese anvil.
Stacy