Suspect in court over 'Punish a Muslim Day' letter
David Parnham, 35, from Lincoln, has been charged with a total of 14 offences.
He appeared at Westminster Magistrates' Court on Friday and was remanded in custody, with the next hearing scheduled for the Old Bailey on 29 June.
Counter Terrorism Policing North East said Mr Parnham was charged "in connection with an ongoing investigation into offensive communications".
He faces: one charge of soliciting to murder; two charges of sending letters promoting 'Punish a Muslim Day'; five counts og sending a hoax noxious substance; five charges under the Malicious Communications Act of sending threatening letters; and one charge of staging a bomb hoax.
Mr Parnham was arrested in Lincoln on Tuesday, police said.
The anonymous letters were reportedly received across England and Wales - including Bradford, East London and Yorkshire. Pictures of the letter were also shared online.
It details a point system for different ways to hurt Muslims, including throwing acid, ripping the hijab off a woman and "butchering" using "gun, knife, vehicle or otherwise" to score points accordingly.
Blowing up a mosque was also on the points system, scoring 1,000 points.
The first 'day', on 3 April, passed without incident. Another letter, calling for attacks against Muslims on 24 July, was circulated at the end of last month.