Big Heart in Chinese / Japanese...

心 would often be translated as “heart.”

However, because it was believed in Chinese culture for thousands of years that your consciousness and thoughts came from the big red organ in the middle of your chest, it also means “mind” or “spirit” and sometimes even “soul.”

In Korean, beyond heart, mind, and spirit, this character can mean moral, nature, mind, affections, intentions, core, and center. In fact, it is used in Chinese to mean “center” as well but only with another character in front of it. For instance, “medical center” or even “shopping center.” Separately and alone, it will not be read with that “center” meaning unless thought of as “the center of your soul.”

隨心而行 is the closest way to express this idea in Chinese. Literally translated, this phrase means “Allow your heart to dictate your behavior” or “Let your heart guide your conduct” in Chinese. You could also translate this as “follow your heart.” Or, with a bit of imagination, it could mean: “let your spirit be your guide.”

Note that in some cases, “heart” can mean “mind,” “soul” or even “spirit” in Chinese. In ancient China, it was thought that the big pumping organ in your chest was where your thoughts came from, or where your soul resides.
Ancient western thought followed a similar belief. Thus phrases like “I love you with all my heart” and “I give you my whole heart.”

四拳波羅蜜大光明 is “shiken haramitsu daikōmyō,” a famous Japanese Buddhist mantra.

四拳 = shi-ken = four fists (many translate this as “four hearts”).
波羅蜜 = ha-ra-mitsu = A loanword representing pāramitā, or entrance into Nirvana. Awkwardly, it also means jackfruit.
大光明 = dai-kou-myo = big/great light bright (great bright light).

Shiken represents four hearts:
1. The Merciful Heart - Love and caring for all living things.
2. The Sincere Heart - Pursues righteousness, or the right path - sincerely trying to do what is right.
3. The Attuned Heart - Knows that nature and fate have their ways, and thus stay in tune with the universe.
4. The Dedicated Heart - Steadfast on the chosen path to the end.

改善 means betterment, improvement, to make better, or to improve - specifically incremental and continuous improvement.

改善 became very important in post-war Japan when Edwards Deming came to Japan to teach concepts of incremental and continuous improvement (for which the big 3 auto-makers did not want to hear about at the time - even kicking Deming out of their offices). The Japanese workforce absorbed this concept when their culture was in flux and primed for change.

This kaizen term is closely associated with the western title “Total Quality Management.” Perhaps dear to my heart since I spent years studying this at university before I moved to China where TQM did not seem to exist. Slowly, this concept has entered China as well (I've actually given lectures on the subject in Beijing).

If you are trying to improve processes at your business or need to remind yourself of your continuous TQM goals, this would be a great wall scroll to hang behind your desk or in your workplace.

See Also:  Kansei