The most basic and formal way to express ability or possibility in Japanese. できる is the potential form of する. For verbs, nominalize with こと before ができる. For nouns (especially Sino-Japanese nouns that can form する-verbs), attach ができる directly. The conjugated potential verb form (e.g. 書ける) is more common in everyday speech, while 〜ことができる is preferred in formal writing and polite speech.

Also appears inImpossibility, Possibility, Difficulty & Ease

Godan (Group I) verbs change their final kana to the corresponding エ段 kana to form the potential. The object particle を typically changes to が with potential verbs (though を is also common in modern Japanese). All godan potential verbs conjugate as ichidan (ru-verbs), e.g. 書ける→書けない→書ければ. This is the most common way to express ability in everyday conversation.

Also appears inImpossibility, Possibility, Difficulty & Ease

Ichidan (Group II) verbs drop る and add られる. In casual speech, られる is often contracted to れる (so-called ら抜き言葉), e.g. 食べれる instead of 食べられる. While widely used in speech, ら抜き is considered non-standard in formal writing and is tested as incorrect on JLPT. The irregular verbs: する→できる (the only suppletive potential), 来る→来られる. Note that 来られる is also the passive form of 来る — context disambiguates.

Some intransitive verbs inherently express potentiality without being conjugated into potential form — the potential meaning is 'built in'. Key distinction: 見える = 'be visible' (the thing naturally comes into view, no agent effort required), while 見られる = 'can see' (the agent can see through their ability or opportunity). Similarly: 聞こえる = 'be audible' (sounds reach the ears naturally) vs 聞ける = 'can hear' (through ability or equipment). Other verbs like 売れる (sell well / be sellable), 解ける (be solvable), 抜ける (be passable through) also carry inherent potential meaning and function as independent intransitive verbs.

Expresses the ease or difficulty of performing an action based on the inherent properties of the object or action itself — not the agent's skill level. 〜やすい and 〜にくい conjugate as i-adjectives. 〜やすい can also attach to non-volitional verbs to mean 'prone to' (e.g. 壊れやすい = fragile / breaks easily, 忘れやすい = easy to forget). Related but distinct forms: 〜づらい (emotionally/psychologically hard to do, N2) and 〜がたい (very difficult, nearly impossible, N1).

Expresses that one cannot do something due to social norms, moral obligations, or external circumstances — NOT physical inability. The speaker could technically do it but feels they must not. The negative form 〜ないわけにはいかない creates a double negative meaning 'cannot not do' = 'must do, have no choice but to'. Different from 〜てはいけない (prohibition directed at the listener) and 〜ことができない (literal/physical inability). Often used to explain why the speaker must decline or act against their own preference.

Expresses that there is objectively no method, means, or way to accomplish something. Unlike 〜わけにはいかない (social/moral inability) or 〜ことができない (personal ability), 〜ようがない focuses on the absence of any possible method — no one could do it under the circumstances. The よう here is the same morpheme as the volitional auxiliary 〜よう, but in this construction it means 'way' or 'method'. 〜ようもない is a stronger, more emphatic variant that adds も ('even a way').

A polite, formal way to express that something is difficult or impossible to do — often used in business settings to decline or express reservation without being blunt. 〜かねます is the polite negative form and is the most common variant. Set expressions: わかりかねます (I'm unable to answer that / I'm afraid I don't know), お受けいたしかねます (we are unable to accept), 賛成しかねます (I find it hard to agree), ご期待に沿いかねます (we may not be able to meet your expectations). Less absolute than a direct negative; maintains the speaker's politeness while setting a boundary.

Expresses that something is very difficult or nearly impossible to do, usually for psychological, emotional, or moral reasons rather than physical ones. More formal and emphatic than 〜にくい. Common collocations: 信じがたい (hard to believe), 許しがたい (unforgivable), 理解しがたい (incomprehensible), 想像しがたい (hard to imagine), 受け入れがたい (unacceptable), 耐えがたい (unbearable). Not used with everyday physical tasks — 食べがたい would sound odd for 'hard to eat' (use 食べにくい instead). This pattern selects for verbs of cognition, emotion, and judgment.

Expresses logical possibility or probability, not physical ability. 得る can be read as either える or うる — うる is more formal/literary and is the only option in the attributive form (連体形) modifying a noun, e.g. 起こりうる事故. The negative 得ない (えない) means 'cannot possibly'. Common uses: あり得る (it's possible), あり得ない (it's impossible / no way), 考え得る (conceivable), 起こり得る (can happen). 〜得る deals with what is within the realm of logical possibility, not what a specific person is capable of doing.

Expresses the frustrating situation where one wants to or tries to do something but external circumstances make it impossible. The structure reduplicates the same verb: first in volitional form (意向形) + にも, then in potential negative form. Common pattern: 〜ようにも〜られない. Emphasizes the speaker's frustration at being blocked by factors beyond their control — 'try as one might, one cannot'. The volitional and potential forms must be from the same verb.

Expresses that something is sufficient, worthy, or qualified for a certain evaluation or action. Often used with verbs like 信頼する (trust), 推薦する (recommend), 評価する (evaluate). The negative forms 〜に足らない and 〜に足りない both mean 'not worth' or 'insignificant' — with 取るに足らない (trivial, insignificant, not worth mentioning) being a very common set phrase. に足る uses the classical attributive form 足る (instead of modern 足りる), giving it a formal, somewhat literary tone. Can also be written 〜に値する (にあたいする) with the same meaning.

Has two distinct usages: (1) With verbs of perception/endurance: にたえる means 'can bear' or 'is worthy of' (e.g. 鑑賞にたえる = stands up to appreciation / is worth viewing). にたえない means 'cannot bear' (e.g. 見るにたえない = too painful/horrible to watch, 聞くにたえない = too awful to listen to). (2) With emotion nouns (感謝, 感激, 同情, etc.): にたえない forms set phrases meaning 'cannot express how much...' — e.g. 感謝にたえません means 'I cannot thank you enough' (NOT 'I am not worthy of thanks'). This is an honorific expression of extreme gratitude or emotion.