Here is the full list of all 26 Pixel Puzzles: Japan achievements. It takes around 8-10 hours to unlock all of the achievements on Windows.
A Mind In Training
Iwakuni Bridge
Komainu No Enryakuji
Osaka Castle
Torii
On The Road To Enlightenment
Urabandai Lakes
Stop The Pop... With A FIsh
Himeji Castle
Pull It OUT!
Red Temple Of Nara
Komainu No Osaka
Zen Garden
All Puzzles Complete!
Consciousness Raised
Enlightenment Attained
Nara Temple Gates
Koen
Cherry Blossom Over Water
Temple Lanterns
Butsudan
Hiroshima Castle Gatehouse
Akai Hashi
Gardens of Nijo Palace
Himeji Castle Gatehouse
Tsukubai