PART II. CRIMES
Chapter VII. Crimes of Harboring Criminals and Suppressing Evidence
Article 104. (Suppression of Evidence)
A person who suppresses, damages, counterfeits or alters evidence relating to a criminal case of another person, or who uses counterfeit or altered evidence, shall be punished by imprisonment with work for not more than 2 years 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.