Chikara is a native Japanese word meaning 'strength, power'. In Chinese characters it is written with one of the simplest and best known characters, 力.
The following sentence, a blurred photo advertising the next edition of a weekly magazine hanging in the middle of a train, uses the kanji:
But the writers of this advertisement obviously felt that something was to be gained by writing chikara in katakana:
A Google search in September 2003 revealed the following distribution on the Internet:
But note that the kanji 力 is found in a lot more words than just chikara, which inflates the figures enormously.