How to turn-off the heuristic guessing of (kanji + okurigana) while doing Japanese input? The Japanese input method has changed on my Mac. The traditional way on OSX and Windows is:  


type hiragana for the word;
press space bar;
use arrow keys to select (kanji + okurigana);
press enter.


Somehow, (95% sure this because of El Capitan) my input method has become:


start typing hiragana;
while still typing hiragana, it continues to take heuristic guesses at the (kanji + okurigana) that I might want. This approach makes most sense on mobile phones, but I don't want to do this on my MacBook!
pressing esc reverts the guessed (kanji + okurigana) back to only hiragana (what I want), but then type another hiragana, and it starts to guess again... this is driving me crazy.


What language settings do I need to adjust so that I can input Japanese as I always have?
That is indeed a new feature for El Capitan:

Mac becomes even more fluent.
Japanese
Live conversion for keyboard input.
OS X El Capitan dramatically improves the ease and speed of entering Japanese text. With an enhanced vocabulary and improved language engine, it automatically transforms Hiragana into written Japanese as you type — eliminating the need to press the space bar for individual word conversions.

You can disable Live Conversion under System Preferences &gt; Keyboard &gt; Input Sources &gt; Japanese, or the shortcut in the Input Menu Item by clicking Open Japanese Preferences: