In Japan we use the solar calendar now, but we used the lunar calendar until in 1872.

Back then, there were leap months, and there where some years when the year had 13 months.

There is the date February 29this year February has 29 days.

Your sentence didn't sound natural.

In Japan we usnow use the solar calendar now, but we used the lunar calendar until in 1872.

I'm also interested in the history of about calendars.

There is the date February 29th.

There is the date February 29thFebruary has a 29th day.

In Japan, we usnow use the solar calendar now, but up until 1872, we used the lunar calendar until in 1872.

Back then, there were leap months, and there were some years when the yearsome years had 13 months.

I'm also interested in the story of aboutbehind the calendar.

or: history behind the calendar

There iIt contains the date February 29th.

The sentence you wrote is grammatically correct, but unusual in this context. Saying "it contains" helps explain how February 29th makes this year a leap year.

In Japan we use a solar calendar now, but we used a lunar calendar until in 1872.

I'm also interested in the story of aboutthe calendar.

You may mean to say, "I'm interested in the history of calendars."

There is the date February 29th.

Your sentence is grammatically correct. But something like "This here has the date February 29th." sounds more natural to me.

In Japan we usnow use the solar calendar now, but we used the lunar calendar until in 1872.

Back then, there were leap months, andso there were some years when the year had 13 months.

I'm also interested in the story of abouties behind calendars.

I'm not completely sure what you mean, so I just guessed.