快 is the single character for “fast” in Chinese.

This applies to race cars, airplanes, rockets, etc.

This can also mean rapid, quick, speed, rate, soon, to make haste, clever, or sharp (of knives or wits). In some context it can mean cheerful or happy.

This is not a common choice for a wall scroll but if you're a speed freak, this may work for you.

Note: In Japanese, this usually has a meaning of pleasure, cheerful, delight, enjoyment, or the female given name Yoshi.

高速 means “high speed” or “in high gear” in Chinese and Japanese Kanji.

In old Korean Hanja, it also means “high speed” but can also be a nickname for “rapid transit.”

高速 is the best selection if you want to say “speed” in regard to your race car, race boat, or lifestyle. You need this word, which literally means “high speed,” as the Asian word for “speed” alone does not suggest whether you mean fast or slow.

緩急 is often used as a Korean martial arts term, “speed control.” It's also one of the 8 key concepts of Tang Soo Do.

In other contexts, this can mean priority, pace, tempo, or slow and fast.

風林火山 is the battle strategy and proverb of Japanese feudal lord Takeda Shingen (1521-1573 AD).

This came from the Art of War by Chinese strategist and tactician Sun Tzu (Sunzi).

You can think of this as an abbreviation to remind officers and troops how to conduct battle.

風林火山 is a word list: Wind, Forest, Fire, Mountain.

The more expanded meaning is supposed to be...

“Swift as the wind, quiet as the forest, fierce as fire, and immovable as a mountain”

“As fast as the wind, as quiet as the forest, as daring as fire, and immovable as the mountain”

“Move as swift as the wind, stay as silent as a forest, attack as fierce as fire, undefeatable defense like a mountain”

“Move swiftly like the wind, stay silent like the forest, attack fiercely like fire, take a tactical position on the mountain”

See Also:  Art of War

慢就是順，順就是快 is the translation to Chinese for “Slow is smooth, smooth is fast” as used by Navy Seals and other military organizations.