Samurai swords have now become illegal weapons under long-awaited new laws.
Selling, making or hiring the elaborate Japanese-style blades now carries up to six months in prison and a fine of up to £5,000.
Higher penalties of up to seven years' imprisonment and an unlimited fine apply to people caught importing the swords.
However, collectors of genuine Japanese swords will be exempt, as will bona fide martial artists and historical re-enactment groups.
The date of the ban was first announced last December.
Home Office minister Vernon Coaker said: "The Government takes violent crime very seriously and we are determined to do all we can to protect individuals and communities.
"Having undertaken a wide consultation we recognise that it is the cheap and easily-available samurai swords that have been used in crime. That is why we have made sensible exemptions for genuine enthusiasts."
He added: "This ban is part of our wider strategy to tackle serious violent crime. Later this year we will launch a new advertising campaign aimed at preventing young people carrying knives."
Association of Chief Police Officers (Acpo) spokesman on knife crime and Deputy Assistant Commissioner of the Metropolitan Police Service, Alf Hitchcock, said: "These are not the most common weapons for people to carry and use in violent crimes, but nationally there have been some significant incidents, serious assaults and murders using a samurai sword. So we feel the introduction of a ban is much needed."
Ex-Liberal Democrat MP Nigel Jones was attacked in 2000 with a samurai sword, in an incident which claimed the life of his political assistant.
