I can't wrap my head around the fact that the populace on all boards is vacillating between thinking Matsuena ended HSDK of his own volition or his new project is a direct sequel.
The majority of commenters' lack of business savviness aside - seriously, the omake chapters were axed, no news of continuation of the OVAs surfaced, the rest of the tankoban releases are going to be pumped out on a monthly basis till Christmas, HSDK has tanked as franchise - even from a mindless content consuming perspective, the fact of the cancelation should not be contested.
Judging by plot developments alone, the cancelation is equally obvious, as in, there was no exposition on Saiga's and Akisame's past, the Elder's and Kushinada's relationship, Ma's army in China, Sakaki being Kenichi's uncle, what's more, Yami's armed division (more than a dozen unique characters) were introduced only to end up fodders. 12 years of work down the gutter in doses of 22 pages, after an announcement about the manga speeding up (Chapter 559).
Anyway, on one hand I'm glad the manga didn't continue its downward slide, it just wasn't the same since the Saiga vs. Hongo arc, on the other I'm bummed that Matsuena couldn't carry out his creative vision and give us an ending befitting the world-building of the previous decade. Here's to hoping the new project will be awesome, I wish him the best of luck with it.
TL;DR: yeayou all read it rigt matsueana quit for the gigles and to mak a sequel a riskier seqell w/ kenichi as a granmaster w/ moe nipples and ass kicking and chinese masters and guns and even more reductionist nonsensical l arguments about the satsujinken and to kenichi to manup and slaughter and for ogata to shine show and apachai to show the bich kushinada whose boss. yea the lazy bastard mangaka