With the exception of counter piracy operations and humanitarian relief activities, have Japanese forces taken part in active operations since World War Two? The 'coalition' in the Gulf does have a realistic chance of exchanging shots if tensions continue or get worse.
Having forces firing shots in anger will be a huge step.
Japanese troops deployed on reconstruction tasks in SE Iraq after 2003 were on strict self-protection ROE, to the extent that they could not offer assistance to any other nationality even in the event of overt attack. It rather irked the Australian Army that their task in MND(SE) was largely to protect the Japanese.