The Bullhead rotates the entire movement so the crown and chronograph pushers sit on top of the case, a decision that makes sense the moment you see one on a rally driver's wrist and at no other time. Forty-four millimeters of 1970s confidence in brown-and-gold or black-and-blue, it has become one of the most collected 6138 models and, by the reference books' own warning, one of the most frankenwatched.
The fraud follows the fame: dials, subdial hands and pushers from parts donors assemble into correct-looking Bullheads constantly, and the two legitimate color schemes have documented details that assembled watches routinely get wrong.
The character actor of the family and the one to buy most carefully. The Bullhead rewards the same discipline as a vintage Submariner at a hundredth the price: every component tells its era, and they must all tell the same one. A watch this distinctive deserves the twenty minutes of photo requests it takes to buy it honestly.
Production windows and specifications compiled from documented collector references and period catalogs, cross-checked across independent sources; manufacturer records for this era are approximate by Seiko's own account.