Since there is a mention of Osaka Castle below, does that mean it has been reduced to one-fourth of its original size?

It was originally four times larger than the current Osaka Castle.
The surrounding castle walls and structures were scaled down, resulting in its current size.
During the first Siege of Osaka, the Winter Campaign, 100,000 troops were stationed inside.
During the second Siege of Osaka, the Summer Campaign, which took place after the moats were filled, more than 50,000 troops were stationed there.
As those who have visited Osaka Castle know, it is massive even now, but if you imagine it being four times larger than it is today,
I don't think it could have ever been conquered if the moats hadn't been filled.