It's split horizontally. An uppercase letter one line above the same lowercase letter produces a full 5x10 letterform.
Unlike other fonts with similar ideas, this one is made in a nonstandardized way. Some letters can be extended beyond 2 lines of height without changing their structure and some can't. By experimenting with these forms one might discover new styles.
Despite what the preview shows, there is no line spacing at all.
"Tameshigiri" means "test cutting".
Original size: 4pt (use multiples of this value for pixel perfection)