Looking at the answer to this question, it seems that both 行かせられる and 行かされる are valid forms of the causative-passive of 行く. I've only been taught the first usage, so I have a number of related questions regarding the difference between the two.

Is the second form a contraction of the first? Is there any difference in nuance between the two? Is the impression that they give when used any different between the two?

Can all 五段 verbs follow this pattern? For example, could 読ませられる be replaced with 読まされる? If this usage is due to a contraction, is there a similar pattern for 一段 verbs? For example, would 出させられる be able to be replaced with an alternate version?

Which usage is used most frequently? And is the same usage used in spoken language as in writing (such as in novels)?

2 Answers 2


More detail about how the causative and passive suffixes evolved.

The causative (-a)せる arose from just plain old す (su), itself the origin of the ubiquitous modern verb する (suru, "to do"). The original meaning was "to do [something]; to make XX do [something]" -- i.e., this served as a causativizing or transitivizing suffix.

Meanwhile, the passive (-a)れる similarly arose from just plain old る (ru). The original meaning was "[something] happens" -- i.e., this functioned as a passivizing or intransitivizing suffix.

In both cases, the root monosyllabic 助動詞 (jodōshi, auxiliary verb) had the classical Japanese conjugation pattern called 下二段 (shimo nidan, "lower two-step"). The "lower" part means the conjugated verb ending alternates between u and e, contrasting with 上 (kami, "upper") verbs that alternate between u and i. As Japanese developed, the root suffix was later conjugated into the 未然形 (mizenkei, incomplete form) of せ or れ, with the verbalizing suffix る added onto the end again.

For modern 五段 (godan, "five step") verbs (so called for the five different vowels that can appear on the end of the verb stem during conjugation), the old root form す can still persist for the causative, resulting in valid grammatical forms like いかす for いかせる, or のます for のませる.

(Note that sometimes the resulting causative form might sound identical to another verb, such as 置かす okasu "to make someone put something somewhere", which sounds identical to 犯す okasu "to violate, to rape". In such cases, the fuller causative form of 置かせる okaseru is probably preferable.)

As such, 行かす is not actually a contraction of 行かせる, and is instead the older form.

The causative and passive endings attach to the 未然形 (mizenkei, irrealis or incomplete form) of the verb stem.

For godan verbs, the mizenkei is the stem form ending in -a, such as 行か (ika) for 行く (iku), 積ま (tsuma) for 積む (tsumu), etc. The passive in classical Japanese was just る for yodan verbs (the precursor to modern godan verbs), developing later into れる, by the same mizenkei + る pattern described below for 出る (ideru). Similarly, the causative was just す, developing later into せる as mizenkei + す.

For nidan (only found in classical Japanese) and ichidan verbs, where the mizenkei stem is the same as the ren'yōkei (continuative) stem, the passive in classical Japanese was らる, developing later into られる. The causative was さす, developing later into させる.

As an aside, the す・る dichotomy for transitive / intransitive persists in numerous modern verb pairs, such as 出る (deru, to go out) and 出す (dasu, to put something out). These two verbs originate from the now-obsolete root verb 出づ (idzu, possibly idu in even older stages of the language). This verb was also a shimo nidan verb. The classical passive or explicitly intransitive form of a verb is [stem in mizenkei] + る. For idzu as a shimo nidan verb, this would be ide + ru, forming ideru. Over time, the initial i- dropped off, producing modern deru.

The causative or explicitly transitive form of idzu should be [stem in mizenkei] + す, or ide + su = idesu, but this pattern is slightly irregular and produced idasu instead, later shortening to dasu. (The shimo nidan causative / transitive pairs like this that I've looked at all take -eru and -asu, instead of the expected -eru and -*esu.)

Other transitive / intransitive pairs like this include:

  • 増える / 増やす (fueru / fuyasu), "to grow or increase by itself" /"to make something grow or increase" (shimo nidan root)
  • 溶ける / 溶かす (tokeru / tokasu), "to melt or dissolve by itself" / "to make something melt or dissolve" (shimo nidan root)
  • 漬かる / 漬かす (tsukaru / tsukasu), "to be in a liquid; to become pickled" / "to stick something into a liquid; to pickle something" (godan root -- つく -- regular passive / causative formation, with idiomatic development over time)

TL;DR: Long story shorter, non-godan verbs cannot take the shorter causative form of す (su) or the shorter passive form of る (ru), due in part to historical development, and due in part to other related verb forms that already take a bare す or る.


Is the second form a contraction of the first?

Yes. 行かされる is a contraction of 行かせられる. (That said, I'm not sure how this came about etymologically.)

Can all 五段 verbs follow this pattern? For example, could 読ませられる be replaced with 読まされる?

Yes. All 五段 verbs may follow this pattern. Thus, 読まされる may be used as the causative passive form of 読む.

If this usage is due to a contraction, is there a similar pattern for 一段 verbs? For example, would 出させられる be able to be replaced with an alternate version?

No: while it might seem like you could contract 食べさせられる to *食べさされる, the latter form is not used; i.e. there is not a similar pattern for 一段 verbs. Hence, the causative passive of 出る【でる】 must be 出させられる【でさせられる】, not *出さされる【でさされる】.

Note that the irregular verbs 来る【くる】 and する also do not admit a contracted form of the causative passive - these remain 来させられる【こさせられる】 and させられる, respectively.

Which usage is used most frequently?

While this will vary depending on context, broadly speaking, the contracted form is more common, in general. (At least, according to a native-speaker teacher of mine - unfortunately, I don't have a better source for this assertion.)

Is there any difference in nuance between the two?

According to this article, yes: there is a difference in nuance between the two. The article uses the following two sentences to illustrate the difference between the two forms of the causative passive:


The first sentence is identified as unacceptable because the form 笑わせられた implies that the speaker was actually forced to laugh, while the form 笑わされた merely implies that came to laugh as a result of some event or happening.

  • @senshin: "許容度に違いが見られます" doesn't necessarily mean 'unacceptable'. To me, 彼の話には笑わせられた is no problem as its own rhetoric, in other words, paraphrasing of 笑うしかなかった.
    – user4092
    Apr 28, 2014 at 8:19

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