Chunks-A Word Building Game (Using Onsets and Rimes) is a great game for children who are reading independently, yet still often sound out new words letter-by-letter of by small pieces at a time. I use a game like this with many of my students who are in third grade and higher who are not confident readers. Many times they have all the skills and chunks needed to sound out new words, but were not taught the tricks of using onsets and rimes to aid in quick identification of new words.
In order to understand the importance of learning onsets and rimes, you will need to be clear of what each is. Education.com defines onsets and rimes as:
"Monosyllabic words can be split into two parts - the onset and the rime -
each of which are smaller than syllables, but may be larger than phonemes.
The onset is the initial consonant sound (b- in bag, sw- in swim), and the rime
is the vowel and the rest of the syllable that follows (-ag in bag, -im in swim)."
If you teach a child to learn to identify the most common onsets and rimes in English, then you are giving him the tools to quickly sound out new unfamiliar words. This game is great at teaching that skill. I suggest with just teaching a few at once if you have a young reader. Also, you can pick one common onset (such as Ch), and show them how it can be used with many different rimes (such as -imp, -ant, -in).