The main part of sad Japanese emoticons is the tears. These are usually shown with a T or sometimes a ;. You can also throw other small circles around the outside of the face to show tears flying as well. You can also use characters like / and \ to cover up their eyes to make it look like the emoticon is sobbing. You can pretty much use whatever you want for a mouth.

 

( ≧Д≦)( p_q)(;*△*;)
((´д`))(´°̥̥̥̥̥̥̥̥ω°̥̥̥̥̥̥̥̥`)(゚´Д`゚)゚
(∩︵∩)(╯︵╰,)
(▰˘︹˘▰)(✖╭╮✖){{p´Д`q}}
ヽ(´□`。)ノ・(/Д`)・・゜・(ノД`)
.・゜゜・(/。\)・゜゜・..·´¯`(>▂<)´¯`·.。・゚゚・(>д<)・゚゚・。
。:゚(。ノω\。)゚・。。:゜(;´∩`;)゜:。。゚( ゚இ‸இ゚)゚。
。゚(゚ノД`゚)゚。。゜(`Д´)゜。( ; ; )
( /)u(\ )( p′︵‵。)( TДT)
(-̩̩-̩̩͡_-̩̩-̩̩͡)(-̩̩̩-̩̩̩-̩̩̩-̩̩̩-̩̩̩___-̩̩̩-̩̩̩-̩̩̩-̩̩̩-̩̩̩)(; T.T))
(;_・)(; ̄д ̄)(;へ:)
(。┰ω┰。)(‘A`)((o(;△;)o))
((T.T; )(︶︹︺)(@´_`@)
(*´;ェ;`*)(*´°̥̥̥̥̥̥̥̥﹏°̥̥̥̥̥̥̥̥ )人(´°̥̥̥̥̥̥̥̥ω°̥̥̥̥̥̥̥̥`)(⁎•̛̣̣꒶̯•̛̣̣⁎)
(/ _ ; )(′︿‵。)
(´_`。)(´_`)(´;ω;`)
(´;д;`)(´;Д;`)(´∩`。)
(´A`。)(´Д`。)(゜´Д`゜)
(|||❛︵❛.)(⊙︿⊙✿)(⌣_⌣”)
(━┳━ _ ━┳━)(┳◇┳)(┳Д┳)
(╥_╥)(▰︶︹︺▰)(iДi)
(o;TωT)o(ʃ⌣́,⌣́ƪ)(T_T)
(T_T)(T⌓T)(T▽T)
(ToT)(πーπ)(இ﹏இ`。)
(っ˘̩╭╮˘̩)っ(ノД`)・゜・。(ㄒoㄒ)
(个_个)༼ ༎ຶ ෴ ༎ຶ༽\(@;◇;@)/
˚‧º·(˚ ˃̣̣̥᷄⌓˂̣̣̥᷅ )‧º·˚°(ಗдಗ。)°.~(。☉︵ ಠ@)>
⊙︿⊙╥﹏╥ヽ(●゚´Д`゚●)ノ゚
o(;△;)oo(╥﹏╥)oo(TヘTo)
p(´⌒`。q)ͼ(ݓ_ݓ)ͽಥ_ಥ
(╥_╥)(/□\*)・゜(∘⁼̴⃙̀˘︷˘⁼̴⃙́∘)
ू(ʚ̴̶̷́ .̠ ʚ̴̶̷̥̀ ू)( -̥̥̥̥̥̥̥̥̥̥̥̥̥̥̥̥̥̥̥̥̥̥̥̥̥᷄◞ω◟-̥̥̥̥̥̥̥̥̥̥̥̥̥̥̥̥̥̥̥̥̥̥̥̥̥᷅ )(づ-̩̩̩-̩̩̩_-̩̩̩-̩̩̩)づ
( °̥̥̥̥̥̥̥̥˟°̥̥̥̥̥̥̥̥ )(ᗒᗣᗕ)՞
૮( ꒦ິ⍣꒦ີ)ა
(.﹒︣︿﹒︣.)(๑꒦ິ ̼ ꒦ິ๑)
⁽ƈ ͡ (ुŏ̥̥̥̥םŏ̥̥̥̥) ु(Θ︹Θ)ს૮(꒦ິཅ꒦ິ)ა
(꒦ິ⍸꒦ິ)…(•̩̩̩̩_•̩̩̩̩)٩꒰´·⌢•`꒱۶⁼³₌₃
ৎ。 ॄཻ͡⁎̥̥̥̥̥̥ૂॽ⁽⁽ƈ  ͡ (ु ˲̥̥̥́ ˱̥̥̥̀) ु⁾⁾(。•́-ก̀。)
(๑´•  .̫ •ू`๑)(≖͞_≖̥).°(ಗдಗ。)°.
(༎ຶ⌑༎ຶ)ৎ⁎́ ॄཻ͡⁎̀ूॽ྆྆(๑˃̥̩̥̥̥̥̆ಐ˂̩̩̥̥̩̥̆৭)
(ఠ్ఠ ˓̭ ఠ్ఠ)(๑′̥̥̥▵‵̥̥̥ ૂ๑):: ˓(ᑊᘩᑊ⁎) ::
˓˓(ᑊᘩᑊ⁎)(๑•́₋•̩̥̀๑)ƈ  ͡ (ुŏ̥̥̥̥ ‸ ŏ̥̥̥̥) ु
(๑◕︵◕๑)