Tabbed from a piano sheet music I found online. Enjoy. -xo
[verse 1]
            FM7             Cadd9
Hitomi no oku ga boyakete mienai
             Fmaj7
Kokoro no soko no
E7                  Gsus4 - G
  kimochi wa aru no?
[refrain 1]
G#m     Am         FM7          C           G  
Sekai no   subete wo   te ni shitatoshite mo
G#m      Am        FM7       G
Sore ga anata no shiawase na no?
[chorus 1]
FM7  C      G6             Am7
   Why? kodoku na sora wo miageru no?
FM7  C      G6          Am7
   Why? waratte misete yo
FM7            C
Kotoba ni suru no ga hetana
G           Am7    G       FM7
Anata no seikaku wakaru kara
     G
Ah ah
[verse 2]
           FM7             Cadd9
Tooi mukashi ni nani ga atta no?
             Fmaj7
Shisen wo sorasu
E7              Gsus4 G
  anata no hitomi ni
[refrain 2]
G#m     Am       FM7          C        G  
Hitori de samishii yoru ni dakishimerareru
G#m   Am     FM7       G
Sonna atatakasa shitteru? Oh
[chorus 2]
FM7  C      G6             Am7
   Why? Doushite katachi ni kodawaru no?
FM7  C      G6          Am7
   Why? kokoro wo hiraite
FM7            C
Ookina ni-mono wo seotta
G           Am7    G       FM7
Anata wo ukeirerareru chikara
     G            FM7
Aruwa shinjite mite
[instrumental] (same bar as chorus 2)
(Oh, yeah, yeah.
Oh, oh, oh, yeah...)
FM7 C G6 Am7
FM7 C G6 Am7
FM7 C
G Am7 G FM7
G FM7
[bridge]
 C  CM7/B Am   C/G FM7  E7   Am/D  Fadd9/G - G
Jiyuu na  hito wa  bukiyou de...
 C  CM7/B Am   C/G FM7  E7 FM7
Jiyuu na  hito wa fuan de...
[last chorus]
FM7  C      G6             Am7
   Why? kodokuna sora wo miageru no?
FM7  C      G6          Am7
   Why? waratte misete yo
FM7            C
Kotoba ni suru no ga hetana
G           Am7    G       FM7
Anata no seikaku wakaru kara
     G
Ah ah
[coda]
            C CM7/B
Shinjite mite
[outro] (same bar as bridge)
(Why? Oh, oh, yeah, yeah.
Why? La, la, ta...
Yeah. Why? Oooh...)
Am C/G FM7 E7 Am/D
Fadd9/G - G
C CM7/B Am C/G FM7 E7 FM7
End in C