On the battlefield of contract trading, defense is the foundation of survival and the prerequisite for victory. Countless investors have validated an iron rule with painful lessons: without defense, one will suffer heavy losses. Leverage is like the sword of Damocles hanging over one's head; it can lead to geometric increases in returns but can also cause risks to spiral out of control in an instant. A moment's carelessness can plunge one into the abyss.

Imagine this scenario: you decisively go long at a market high, only to encounter a black swan event, causing prices to plummet in an avalanche. If you haven't set a stop-loss in advance, losses will expand rapidly like a snowball, and within minutes, not only will your principal be wiped out, but it might even trigger a liquidation mechanism. Even if the market reverses later, your account has already hit zero, and all hopes have turned to bubbles—this is the price of not having defense.

A stop-loss is undoubtedly the most solid shield in the defense system. It is a predetermined 'safety line' based on individual risk tolerance and trading strategy. Once the market reaches this line, the system immediately executes a closing order, keeping losses within a bearable range. Just like a seatbelt fastened while driving, it builds a final line of defense for your funds during market turbulence. Ignoring a stop-loss is akin to abandoning ship and swimming naked in a storm; short-term lucky profits will ultimately be devoured by a single fatal mistake.

On the other hand, taking profit is another key dimension of the defense strategy. It helps investors lock in gains in a timely manner and avoid profit withdrawal caused by sudden market shifts. Contract trading is inherently full of uncertainties, with market conditions changing rapidly. Only by simultaneously controlling both stop-loss and take-profit can one maintain a foothold in a market where risks and opportunities coexist. First ensure survival, then pursue profits; this is not only the wisdom of trading but also the core principle for steady and long-term success in the contract market.