Why is kiru represented as kiri in おじいさん が 山 へ 木 を きり に いけば


I can't fathom why the verb kiru is in the masu form without the masu attached
in this sentence:

> おじいさん が 山{やま} へ 木{き} を きり に いけば

What is the purpose?




You may make sense of this grammar pattern if you know [the masu-stem of a
verb can act as a noun](https://japanese.stackexchange.com/a/32311/5010). As
you probably know, に is a particle that usually takes a **noun** representing
a destination, a goal, a resulting status, etc. It roughly corresponds to the
English prepositions _to_ , _for_ or _into_.

So you can use ～に行く with simple nouns and suru-verbs:

  * 買い物に行く to go for shopping
  * 面接に来る to come to take a job interview

Likewise, when you use ～に行く with a verb representing a purpose, a form that
has a noun-like quality is expected, and this is where the masu-stem comes
into play:

  * 映画を見に行く
  * 遊びに出かける

That being said, I think this `masu-stem + motion verb` construction should be
learned by rote. So-called "masu-stem" has various usages, and it may not be
always possible to explain it logically. After all, "masu-stem" (or 連用形) was
named after its most important function, but its usage is not limited to what
the name suggests. See [this](https://japanese.stackexchange.com/a/65953/5010)
for details.




You may make sense of this grammar pattern if you know [the masu-stem of a
verb can act as a noun](https://japanese.stackexchange.com/a/32311/5010). As
you probably know, に is a particle that usually takes a **noun** representing
a destination, a goal, a resulting status, etc. It roughly corresponds to the
English prepositions _to_ , _for_ or _into_.

So you can use ～に行く with simple nouns and suru-verbs:

  * 買い物に行く to go for shopping
  * 面接に来る to come to take a job interview

Likewise, when you use ～に行く with a verb representing a purpose, a form that
has a noun-like quality is expected, and this is where the masu-stem comes
into play:

  * 映画を見に行く
  * 遊びに出かける

That being said, I think this `masu-stem + motion verb` construction should be
learned by rote. So-called "masu-stem" has various usages, and it may not be
always possible to explain it logically. After all, "masu-stem" (or 連用形) was
named after its most important function, but its usage is not limited to what
the name suggests. See [this](https://japanese.stackexchange.com/a/65953/5010)
for details.

