A gentleman`s agreement, defined at the beginning of the 20th century as “an agreement between gentlemen who looks at price control,” has been described by one source as the most lax form of a “pool.”  Such agreements have been declared in all industrial sectors and are numerous in the steel and steel industry.  Gentlemen`s agreements, because they are informal and often not written, do not enjoy the same legal and regulatory protection as a formal contract and are therefore more difficult to implement. Despite their informal nature, the violation of a gentlemen`s agreement could have negative consequences on trade relations if a party decides not to keep its promise. A gentlemen`s agreement can also be described as a “gentleman`s agreement” and can be completed by a handshake or not. Gentlemen`s agreements can also be found in trade agreements and international relations. One example is the 1907 Gentlemen`s Agreement, in which the United States and the Japanese Empire addressed immigration from Japan and the mistreatment of Japanese immigrants to the United States. The agreement, which was never ratified by Congress, saw Japan stop issuing passports to people who wanted to immigrate to America to work. The United States, on the other hand, would no longer allow discrimination and segregation of Japanese citizens residing in America. In the automotive industry, Japanese manufacturers have agreed that no standard vehicle would have more than 276 hp (206 kW; 280 CH); The agreement ended in 2005.
 German manufacturers limit the maximum speed of high-performance sedans (berlines) and breaks to 250 km/h.   When the Suzuki Hayabusa motorcycle exceeded 310 km/h in 1999, fears of a European ban or regulatory intervention led Japanese and European manufacturers to limit to 300 km/h at the end of 1999 See list of the fastest series bikes. Gentlemen`s agreements were a widespread discriminatory tactic, which would have been more common than restrictive alliances to maintain the homogeneity of upper-class neighborhoods and suburbs in the United States.  The nature of these agreements made it extremely difficult to prove or follow them, and they were long after the U.S. Supreme Court decisions in Shelley/.