PART II. CRIMES
Chapter VII. Crimes of Harboring Criminals and Suppressing Evidence
Article 105-2. (Intimidation of Witnesses)
A person who, in relation to his/her own criminal case or the criminal case of another person, forcibly demands without justifiable grounds a meeting with any person or intimidates any person deemed to have knowledge necessary for investigation or trial of such case, or a relative of such person, shall be punished by imprisonment with work for not more than 1 year or a fine of not more than 200,000 yen.
Offences against administration of justice
Corruptly influencing a witness, obstructing or interfering with the attendance or testimony of a witness, retaliating against a witness for giving testimony or destroying, tampering with or interfering with the collection of evidence
National penalties - offences against the administration of justice
National penalties - maximum penalty
EDIT.