Is Rokuyō a religion?

We've mentioned Rokuyō's connection with Buddha. Does that mean Rokuyō is a religious tool?

Well, you'll have noticed Rokuyō is quite balanced with symmetrically-reversed meanings in the six days:

Senshō
Good luck in the morning, bad luck in the afternoon
<—>Sakimake
Bad luck in the morning, good luck in the afternoon
Tomobiki
Good luck all day, except at noon
<—>Shakku
Bad luck all day, except at noon
Taian
Good luck all day
<—>Butsumetsu
Bad luck all day

Rokuyō is also quite balanced with an equal amount of  good fortune  and  misfortune,  as shown in this Fortune Indicator:

Fortune Indicator
a.m.noonp.m.
Senshō
 
good fortune in the morning, misfortune in the afternoon
Tomobiki
 
good fortune all day except at noon
Sakimake
 
misfortune in the morning, good fortune in the afternoon
Butsumetsu
 
misfortune all day
Taian
 
good fortune all day
Shakku
 
misfortune all day except at noon

This Onmyō (Yin-Yang) harmony brings elements of Buddhism, Daoism and Shinto into a syncretic philosophy but doesn't make Rokuyō a religion in the generally accepted sense of the word.

Similarly, Rokuyō is not a variation of the Chinese Feng Shui. While both the Rokuyō calendar and the Feng Shui calendar calculations depend on the lunar calendar and both involve the concept of auspicious dates, they are distinct systems with their own cultural backgrounds and applications.

Rokuyō and Feng Shui are two different systems and serve different purposes.

Many words which seem to be associated with butsuji (Buddhist memorial service) are used but in reality they are just phonetic equivalents. The most widely-practiced branch of Buddhism in Japan (Jōdo Shinshū) emphatically warns against fortune-telling. Superstition in general is taboo.

The Butsumetsu kigen is certainly the Buddhist calendar in Japan, but just as Santa Claus is not a saint revered by Christianity, the Rokuyō's Butsumetsu is not a day of Buddhist observance.