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
On The Road To Enlightenment
All Puzzles Complete!
Tsukubai
Enlightenment Attained
Himeji Castle Gatehouse
Gardens of Nijo Palace
Akai Hashi
Hiroshima Castle Gatehouse
Consciousness Raised
Cherry Blossom Over Water
Butsudan
Temple Lanterns
Koen
Nara Temple Gates
Iwakuni Bridge
Komainu No Enryakuji
Osaka Castle
Torii
Urabandai Lakes
Himeji Castle
Red Temple Of Nara
Komainu No Osaka
Zen Garden
Stop The Pop... With A FIsh
Pull It OUT!