Passive form

The passive voice is a vital part of Japanese communication. It is categorized into two main types:

1. Direct Passive: Similar to English, where the object of an active sentence becomes the subject. The agent (doer) is marked with the particle に. Direct passives are frequently used with inanimate subjects to state objective facts or historical events (e.g., この本は1990年に書かれた - This book was written in 1990).
2. Indirect (Adversative) Passive: This is highly distinctive of Japanese and has no direct equivalent in English. It describes an event that affects the subject, even if they weren't the direct object. It generally implies the subject was inconvenienced or 'suffered' from the action. Crucially, intransitive verbs (verbs that cannot take a direct object, like 'to rain' or 'to cry') can be used in this passive form to show inconvenience. Standard transitive verbs can also form indirect passives when the subject is an affected third party (e.g., 妹にケーキを食べられた - I had my cake eaten by my little sister). Additionally, when an action is done to a body part or possession, the owner becomes the subject, while the item remains marked by the を particle. Note that while indirect passives usually imply suffering, possessor passives can be positive if the verb is positive (e.g., 先生に発音を褒められた - I had my pronunciation praised by the teacher).

Conjugation Rules:

• Group 1 (Godan): Change the final -u sound to -a and add れる. For verbs ending in a single う, change it to わ (e.g., 買う（かう） → 買われる（かわれる）).
• Group 2 (Ichidan): Drop the final る and add られる (e.g., 食べる（たべる） → 食べられる（たべられる）).
• Group 3 (Irregular): する becomes される; 来る（くる） becomes 来られる（こられる）.

Register Nuance & Agent Markers:
While に is the standard agent marker, によって is used in formal or literary contexts, especially when referring to creators or inventors in direct passives with inanimate subjects. Furthermore, から is frequently used instead of に when the agent is viewed as a source (such as of communication, a gift, or emotion, e.g., 先生から褒められた - I was praised by the teacher). Note that によって is generally restricted to Direct Passives.

Other Uses & Notes:

• Potential Form Overlap: For Group 2 verbs and 来る（くる）, the passive form is identical to the potential form (e.g., 食べられる（たべられる） can mean 'is eaten' or 'can eat'). Context is key to distinguishing them.
• Honorific Usage: The passive form is frequently used as a polite or honorific form to show respect to the subject's actions.
• Spontaneous (自発): The passive form can also express spontaneous thoughts or feelings that naturally arise (e.g., 思われる, 感じられる). Together with Passive, Potential, and Honorific, these make up the four main functions of れる/られる.
• Agent Omission: The agent (doer) is frequently omitted when it is obvious, unknown, or unimportant.