Different kanji for "akeru" あける：開ける、空ける、明ける

Jim Breen's EDICT doesn't really provide the difference between the three different ways to write "akeru": 開ける、空ける、明ける, so I'm going to write this article for my reference. I hope others will find this useful as well. All definitions come from Kenkyusha's 5th Shinwaei Chuujiten and the Daijiten (研究者新和英中辞典・大辞典) as well.



開ける
This is a transitive verb that means "to open" things like parcels, boxes, wrappers, bottles, etc. It can also be used for doors and books.
It is also used in the sense of "boring a hole", as in 穴を開ける.
A third definition (that I haven't seen used ever) is 使わないでおく、取っておく, as in
今度の土曜日は私のために開けておいていただけませんか。
Will you keep next Saturday free for me, please?

空ける
This is also a transitive verb that means "to empty, to vacate". Recall that the kanji 空 means "empty" or "atmosphere".
ex.
家を空ける
Ie wo akeru = leave the house
道を空ける
Michi wo akeru = make way (for)
鍋にミルクを空ける
Nabe ni miruku wo akeru = empty the milk into the pan
場所を空ける
Basho wo akeru = make room (for)
一晩でウイスキーを一瓶皆で空けてしまった.
Hitoban de uiskii wo hitobin mina de akete shimatta.
In one evening, we drank up one bottle of whiskey among us.

明ける
The Kenkyuusha Shinwaei Daijiten lists three definitions for this: (a) dawn, (b) begin, and (c) end. However, if one looks at the example sentences provided in the Daijiten, all uses can be encompassed by the meaning "end".

The first definition occurs mainly in the set phrase "yoru ga akeru":
夜が明ける = day breaks = night ends
It also occurs in an idiomatic phrase 夜も日も明けない "yoru mo hi mo akenai" which means that something is too important that one cannot live without it.

Consider the second definition, for which the Daijiten gives the following sentences:

年が明けると彼女は 18 になる. She'll be eighteen in the new year.
Toshi ga akeru to kanojo wa juuhassai ni naru.
lit. When the year ends, she'll be 18.

明けましておめでとう. A Happy New Year (to you)!
Akemashite omedetou!
lit. (The year) has ended and rejoice.

As we can see, 明ける is used for periodic events - when one thing ends, another begins.

Other sentences:

梅雨が明けるのが待ち遠しい. I can't wait for the rainy season to end.
年季が明けたら故郷(くに)へ帰れる, そう思えば仕事もつらくない. When I think of being able to return home after my apprenticeship is over, the work isn't so hard.
祖父の喪が明けるのを待って私は結婚する予定です. I plan to wait until the period of mourning for my grandfather is over before I get married.
寒は昨日明けた. Winter was over yesterday according to the calendar.