気の強い means strong-willed or strong of heart in Japanese.

Here's the character breakdown of this Japanese title:
気 (ki) spirit; mind; heart; nature; motivation; intention; feelings; essence.
の (no) possessive particle.
強い (tsuyoi) strong; powerful; mighty; potent; resistant; resilient; durable.

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

意志堅強 can mean either “strong-hearted,” “strong-willed” or “determination.”

The first two characters can mean “will,” “willpower,” “determination,” “volition,” “intention,” or “intent.” But, it should be noted that this first part possesses the element of “heart” in the lower portion of both characters (they also partially carry the meaning “with the whole heart”).

The last two characters mean “strong” or “staunch.”

Chinese word order and grammar are a bit different than English, so in this case, they are in reverse order of English but have the correct meaning in a natural form.

See Also:  Strong Willed | Discipline | Will-Power / Self

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.”

思い切り can mean “with all one's strength,” “with all one's heart,” “to the limits of your heart,” or “to the end of your heart/emotions.”

The character breakdown:
思い (omoi) thought; mind; heart; feelings; emotion; sentiment; love; affection; desire; wish; hope; expectation; imagination; experience
切り (kiri) bounds; limits.

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

有志者事竟成 is an old Chinese proverb that has been translated many different ways into English. As you read the translations below, keep in mind that in Chinese, heart=mind.

Nothing is impossible to a willing heart.
Nothing is impossible to a willing mind.
Nothing is difficult to a willing heart.
Where there is a will, there is a way.
Nothing in the world is impossible if you set your mind to doing it.
A willful man will have his way.
If you wish it, you will do it.
A determined heart can accomplish anything.
All things are possible with a strong mind.

不動心 is one of the five spirits of the warrior (budo) and is often used as a Japanese martial arts tenet.

Under that context, places such as the Budo Dojo define it this way: An unshakable mind and an immovable spirit is the state of fudoshin. It is courage and stability displayed both mentally and physically. Rather than indicating rigidity and inflexibility, fudoshin describes a condition that is not easily upset by internal thoughts or external forces. It is capable of receiving a strong attack while retaining composure and balance. It receives and yields lightly, grounds to the earth, and reflects aggression back to the source.

Other translations of this title include unwavering mind, immovable mind, unwavering composure, imperturbability, steadfastness, keeping a cool head in an emergency, or keeping one's calm (during a fight).

The first two Kanji alone mean immobility, firmness, fixed, steadfastness, motionless, and idle.

The last Kanji means heart, mind, soul, or essence.

Together, these three Kanji create a title defined as “immovable mind” within the context of Japanese martial arts. However, in Chinese, it would mean “motionless heart,” and in Korean Hanja, “wafting heart” or “floating heart.”

精神力量 is a title that speaks of one's soul or spirit and the capacity or strength that soul possesses.

The first two characters mean mind, heart, spirit, and/or soul.

The last two characters mean strength, capacity, or ability.

Note: Separately, these are two words in Japanese and can be pronounced, but this does not make a natural title in Japanese (best if your audience is Chinese).

強い体強い心 is a way to write “strong mind, strong body” in Japanese.

Each of the two lines starts with 強い (tsuyoi) which means: strong; powerful; mighty; potent; resistant; resilient; durable; tough; stiff; hard; inflexible.

The body is represented with 体 (the ancient version is 體, romanized as karada), which means: body; build; physique; posture; torso; trunk; health.

Mind is represented with 心 (kokoro), which can mean heart, mind, or soul, depending on context.

強い體強い心 is not a common phrase in Japanese, so it's not the most natural title for calligraphy. In English, you might want to write it, “strong mind, strong body” but, “strong mind, strong body,” is more natural in Japanese.

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

強壯 is an adjective that means powerful or strong.

It can also be translated as able-bodied, robust, or sturdy.
This version of strength also suggests muscularity.

Note that the second character was simplified in Japan after WWII (also simplified in mainland China but not for calligraphy). If you want the modern Japanese/simplified version, please click on the Kanji shown to the right.

See Also:  With All the Strength of Your Heart | Vitality | Strong / Healthy

力 is the simplest form of “power” or “strength.”

In Japanese, it is pronounced “chikara” when used alone, and “ryoku” when used in a sentence (there are also a few other possible pronunciations of this Kanji in Japanese).

In some contexts, this can mean ability, force, physical strength, capability, and influence.

See Also:  With All the Strength of Your Heart | Vitality | Strong / Healthy

毅 is the simplest way to express perseverance in Chinese and Korean Hanja.
This single-character version leaves a bit of mystery about what kind of perseverance you might want to convey.

In Korean, this is usually associated with “strength of character.”

In Japanese, this character can be pronounced in a dozen different ways (so we have left out the Japanese pronunciation guide that normally appears above). In Japanese, this Kanji would usually be translated as “strong” (perhaps strong-willed).

See Also:  Tenacious / Tenacity | Perseverance / Indomitable / Invincible Fortitude | With All the Strength of Your Heart | Carry On | Undaunted

剛毅 is a Japanese and Chinese word that means resolute and firm, fortitude, firmness of character, hardihood, manliness, or macho.

See Also:  Perseverance | With All the Strength of Your Heart | Tenacious / Tenacity

不屈 is the short form of a longer Chinese word and also a word used in Korean and Japanese to express the idea of being indomitable. It literally means “will not bend,” “will not crouch,” “will not yield,” “will not flinch,” or “will not submit.”

Note: Some will translate this as “indomitable spirit”; however, technically, there is no character to suggest the idea of “spirit” in this word.

See Also:  Tenacious / Tenacity | Perseverance / Indomitable / Invincible Fortitude | With All the Strength of Your Heart | Carry On | Undaunted

不屈不撓 means “Indomitable” or “Unyielding.”

不屈不撓 is a long word by Chinese standards. At least, it is often translated as a single word into English. It's actually a proverb in Chinese.

If you want to break it down, you can see that the first and third characters are the same. Both mean “not” (they work as a suffix to make a negative or opposite meaning to whatever character follows).

The second character means “bendable.”

The last means “scratched” or “bothered.”

So this really means “Won't be bent, can't be bothered.” I have also seen it written as “Will not crouch, will not submit.” This comes from the fact that the second character can mean “to crouch” and the last can mean “to submit” (as in “to give in” such as “submitting to the rule of someone else”). This may explain better why these four characters mean “indomitable.”

Notes:
Some will translate this as “indomitable spirit”; however, technically, there is no character to suggest the idea of “spirit” in this word.
Other translations include indefatigability, indomitableness, or unremitting tenacity.

The first two characters can be stand-alone words in Chinese.
In Japanese, this is considered two words (with very similar meanings). It's more common to see the word order flipped to 不撓不屈 in Japanese.
The same characters are used in old Korean Hanja. Just like in Japanese, the words are swapped to 不撓不屈 creating a word pronounced “불요불굴” in Korean.

See 不撓不屈

See Also:  Tenacious / Tenacity | Perseverance / Indomitable / Invincible Fortitude | With All the Strength of Your Heart | Carry On | Undaunted

If you are into healthy living, 健康生活 might be an excellent selection for a wall scroll to hang in your home.

The first two characters speak of health, vitality, vigor, and being of sound body. The second two characters mean living or life (daily existence).

See Also:  With All the Strength of Your Heart | Vitality | Strong / Healthy

百折不撓 is a Chinese proverb that means “Be undaunted in the face of repeated setbacks.”

More directly translated, it reads, “[Overcome] a hundred setbacks, without flinching.” 百折不撓 is of Chinese origin but is commonly used in Japanese and somewhat in Korean (same characters, different pronunciation).

This proverb comes from a long, and occasionally tragic story of a man that lived sometime around 25-220 AD. His name was Qiao Xuan, and he never stooped to flattery but remained an upright person at all times. He fought to expose the corruption of higher-level government officials at great risk to himself.

Then when he was at a higher level in the Imperial Court, bandits were regularly capturing hostages and demanding ransoms. But when his own son was captured, he was so focused on his duty to the Emperor and the common good that he sent a platoon of soldiers to raid the bandits' hideout, and stop them once and for all even at the risk of his own son's life. While all of the bandits were arrested in the raid, they killed Qiao Xuan's son at first sight of the raiding soldiers.

Near the end of his career, a new Emperor came to power, and Qiao Xuan reported to him that one of his ministers was bullying the people and extorting money from them. The new Emperor refused to listen to Qiao Xuan and even promoted the corrupt Minister. Qiao Xuan was so disgusted that in protest, he resigned from his post as minister (something almost never done) and left for his home village.

His tombstone reads “Bai Zhe Bu Nao” which is now a proverb used in Chinese culture to describe a person of strong will who puts up stubborn resistance against great odds.

My Chinese-English dictionary defines these 4 characters as “keep on fighting despite all setbacks,” “be undaunted by repeated setbacks,” and “be indomitable.”

Our translator says it can mean “never give up” in modern Chinese.

Although the first two characters are translated correctly as “repeated setbacks,” the literal meaning is “100 setbacks” or “a rope that breaks 100 times.” The last two characters can mean “do not yield” or “do not give up.”
Most Chinese, Japanese, and Korean people will not take this absolutely literal meaning but will instead understand it as the title suggests above. If you want a single big word definition, it would be indefatigability, indomitableness, persistence, or unyielding.

See Also:  Tenacious / Tenacity | Perseverance / Indomitable / Invincible Fortitude | With All the Strength of Your Heart | Perseverance | Persistence