The name The Guts Theory in Chinese / Japanese...

根性論 is a Japanese title that refers to the belief that where there's a will, there's a way.

Another way to translate this is “The Guts Theory” or “The Doctrine of Will-Power.” Maybe breaking down the meaning of the characters will help clarify this:
根性 = will-power; guts; temper; nature; spirit; nature and character; the nature of the powers of any sense.
論 = theory; doctrine; treatises on dogma, philosophy, discipline, etc.

進化論 can be translated as “Darwin's theory of evolution,” “evolutionary theory,” or “theory of evolution.”

Same translation for Chinese, Japanese, and old Korean. Therefore, this title is very universal.

While difficult to translate “No guts no glory,” into Mandarin Chinese, 無勇不榮 is kind of close.

The first two characters mean “without bravery,” or “without courage.” In this case, bravery/courage is a stand-in for “guts.”

The last two characters mean “no glory.”

The idea that guts (internal organs) are somehow equal to courage, does not crossover to Chinese. However, translating the phrase back from Chinese to English, you get, “No Courage, No Glory,” which is pretty close to the intended idea.

腹が据わる is a Japanese proverb that means to have guts or to be unwavering in one's resolution.

Note: Because this selection contains some special Japanese Hiragana characters, it should be written by a Japanese calligrapher.

理念/理唸 means idea, notion, concept, principle, theory, philosophy*, or doctrine in Chinese, Japanese Kanji, and old Korean Hanja.

This word is OK for a wall scroll, although it's more commonly used as an oral/informal word in Asia.

* This is not the title for philosophy but rather is about having a certain philosophy or approach to something.

鉄心石腸 is a Japanese proverb that suggests you should have the inner-strength and will as hard and steadfast as iron.

It's the Japanese way of saying, “stay strong.” This is an especially uplifting thing to say to a person in distress or recovering from a disaster. It's kind of the survivor's creed.

If you literally translate this, it means “iron will, stone guts” or “iron heart, rock-hard bowels.”

Depending on the romanization scheme you use, this man's name can be spelled Laozi, Lao Tzu, or Lao Tze. In older English usage, he was known as Laocius. He is believed to have lived around 500 B.C.

He was a Chinese philosopher, founder of Daoism/Taoism, credited with being the author of the sacred and wise book of Daoism/Taoism.

There is a theory that Lao Tzu's soul traveled to India and was reborn as the Buddha.

不來不去 is a Buddhist term, originally anāgamana-nirgama from Sanskrit.

This implies that things are neither coming into nor going out of existence.

This can also mean “all things are eternal,” or others will call this the Buddhist concept of the eternal conservation of energy.

This theory predates Albert Einstein and Isaac Newton.

Note: 不來不去 is not a well-known word for both Buddhists and non-Buddhists, so not all will recognize it.

迫力 is a Chinese word that is a form of personal strength.

It is a word that describes a person who is willing to take a risk. In English, we might say, “Someone with guts.”

An example might be a person that is not rich but invests a lot of money into something (knowing they could double their money or lose it all). Win or lose, this is a person that knows or pushes their potential.

Tearing this word apart, the first character means “to compel,” urgent, urge, force, imminent, or “spur on.” The second means power, strong, bear, or exert.

Note: 迫力 is also a word in Japanese Kanji and Korean Hanja but with a meaning more like force, intensity, appeal, strength, impact, force, or simply power.

勇氣 is one of several ways to express bravery and courage in Chinese, Japanese, and Korean.

This version is the most spiritual. This is the essence of bravery from deep within your being. This is the mental state of being brave versus actual brave behavior. You'd more likely use this to say, “He is very courageous,” rather than “He fought courageously in the battle.”

The first character also means bravery or courage when it's seen alone. With the second character added, an element of energy or spirit is added. The second character is the same “chi” or “qi” energy that Kung Fu masters focus on when they strike. For this reason, you could say this means “spirit of courage” or “brave spirit.”

This is certainly a stronger word than just the first character alone.

Beyond bravery or courage, dictionaries also translate this word as valor/valour, nerve, audacity, daring, pluck, plucky, gallantry, guts, gutsy, and boldness.

This is also one of the 8 key concepts of tang soo do.

While the version shown to the left is commonly used in Chinese and Korean Hanja (and ancient Japanese Kanji), please note that the second character is written with slightly fewer strokes in modern Japanese. If you want the modern Japanese version, please click on the character to the right. Both styles would be understood by native Chinese, Japanese, and many (but not all) Korean people. You should make your selection based on the intended audience for your calligraphy artwork. Or pick the single-character form of bravery/courage which is universal.

虚実 is a Japanese word that means “falsehood [and] truth” or “fiction [and] fact.”

This concept is used in warfare, gameplay, and martial arts strategies. 虚実 can be a strategy of real and/or deceptive moves. This gets to some Sun Tzu Art of War stuff where in warfare a strategic move is either a real and serious move or it is a deceptive blow.

Let's explore each character in more depth:

虚 was originally written 虛 (there is a very subtle difference in the strokes at the bottom of the character) and means unpreparedness, falsehood, emptiness, void, abstract theory, empty or unoccupied, diffident or timid, false, humble or modest, virtual, or in vain.
In the Buddhist context, 虛 represents the Pali/Sanskrit word “śūnya,” meaning empty, vacant, unreal, unsubstantial, untrue, space, humble, or in vain.
In ancient Eastern/Chinese astronomy, 虛 represents the “Emptiness” constellation (one of the 28 mansions in the sky).

実 was originally 實 in Chinese (they currently write it as 实 in Simplified Chinese) with the meaning, truth, reality, sincerity, honesty, fidelity, and substance.
The Buddhist context is similar, adding real, true, honest, really, solid, definitely, sincere, solid, fixed, full, to fill, fruit, kernel, verily, in fact, the supreme fact, or ultimate reality to the definition.