Many people get excited when they see a stock hit the daily limit, but they can't really tell whether the limit-up is strong or weak. The secret actually lies in the order book—just look at the封单比 (order book ratio).

What is the封单比? Simply put, it's the ratio of the封单量 (order book volume) to the total trading volume of the day. This number can directly reflect the true intentions of the main players, much more reliable than just looking at the time of the limit-up.

Let's categorize the situations into three types:

**Type 1:封单比 less than 1**. This indicates very little order book volume, meaning the main players aren't very enthusiastic. If someone suddenly hits a large sell order, this limit-up will immediately break. This kind of limit-up can be considered relatively weak.

**Type 2:封单比 between 1 and 5**. This is a normal level, representing a moderately strong limit-up. If this ratio is maintained throughout the day without large sell-offs, it can be considered somewhat strong. Usually, non-leader stocks tend to show this pattern.

**Type 3:封单比 greater than 5**. This is the real heavy hitter. Usually only the sector leaders can reach this level, indicating that the main players are fully in control. No matter how many sell orders come in, they can't break this封单比, meaning market disagreement has been mostly digested. Trying to place an order at this point? That's basically a dream.

To put it simply, just look at the封单数 in the order book—it can tell you exactly how strong the main players are. This is the most fundamental skill, and you must master it.