Stacking stones, having them collapse, and stacking again.
I created a browser game called "Sai no Kawara" inspired by this concept.
At first, there's almost nothing you can do. In the riverbed before you, you stack stones. That's all.
However, as you continue stacking, the situation gradually changes. Jizo statues increase, merit accumulates, time flows, and eventually the riverbed becomes something you couldn't have imagined from the initial screen.
## What Kind of Game is "Sai no Kawara"?
"Sai no Kawara" is a browser game where you continuously stack stones while transforming the riverbed.
Right after starting, the riverbed has almost nothing. When you press "Stack" at the bottom of the screen, stones increase, and from there the game gradually begins to move.
It's not just about increasing numbers—as you progress, new Jizo statues appear and a separate value called "merit" increases. Once you reach a certain point, you'll see choices that weren't available before.
And in this riverbed, time itself flows.
It progresses through 10 years, 100 years, 10,000 years, and continues to time periods you'd rarely see in ordinary games.
## Stacked Stones Don't Always Remain Forever
In this game, the stones you've stacked don't remain eternally as they are.
At the bottom of the screen there is "the presence of demons," and the riverbed has a rule that "if collapsed, it becomes impermanence."
There's a possibility that what you've worked to build will be lost. Yet, you stack again.
This "it doesn't end with increasing" is one of the elements I wanted to preserve in creating "Sai no Kawara."
If we only wanted to efficiently increase numbers, we could make a much simpler idle game. However, that would diminish the meaning of using Sai no Kawara as the subject matter.
Both the act of stacking and the loss of what has been stacked exist within the game.
As you continue stacking stones, various Jizo statues appear in the riverbed.
Not just the stone Jizo you see at first, but as you progress, Mizuko Jizo, Enmei Jizo, Rokudo Jizo, and others are unlocked.
Each Jizo has different roles, and changes occur in stone stacking speed and how merit increases.
The riverbed where you initially stacked stones one by one becomes quite different as you progress.
In fact, in this playthrough, the riverbed that had almost no stones in the early stages transforms into a place with tens of millions of stones and numerous Jizo statues when played for a long time.
Observing "how a place with nothing changes" is also one way to enjoy this game.
As you progress through the game, "merit" accumulates separately from stones.
And once you reach a certain point, a mechanism called "samsara" appears.
In samsara, instead of maintaining the stones you've stacked and the Jizo statues you've summoned in the riverbed, you can proceed to the next life.
However, what you can take with you and what wishes you choose will affect how things progress afterward.
Rather than a game where you maintain what you've built, there's an option to let go once and move forward. This mechanism is also placed at the center of "Sai no Kawara."
Since explaining the samsara mechanism would become quite lengthy, I plan to detail it in a separate article.
"Sai no Kawara" includes elements that appear under slightly different conditions than normal progression.
For example, names like "Ushi no Koku Mairi," "Bonno," "Tsuki Machi," and "Roku Jizo" exist meaningfully within the game.
If I revealed all the conditions from the start, there would be no point in searching for them, so I won't write the details here.
Rather than just aiming to increase numbers, I've left parts where you might think "this probably has some condition" and try different actions.
You can enjoy it by progressing normally, but if something catches your interest, try acting differently.
I plan to create a separate article with "hints only" rather than complete answers for the hidden elements.
Right after starting, "Sai no Kawara" is quite quiet.
There are almost no stones, no Jizo statues, just the riverbed and the moon.
However, as you play for a long time, the screen fills with massive numbers of stones and Jizo statues, merit values grow large, and elapsed time extends to hundreds of millions of years.
In this playthrough, time progressed to 2.55 billion years.
At this point, the act of "stacking one stone" right after starting and the state where massive things are moving across the entire screen look almost like completely different games.
However, the fundamental thing you're doing hasn't changed.
Stacking stones.
As a result of continuing that endlessly, the riverbed itself transforms.
In the game, you can switch between Japanese and English, Traditional Chinese, Simplified Chinese, and Korean.
Additionally, you can change environmental sound and effect sound volume, effect intensity, and number notation methods from settings.
For numbers, you can switch between Japanese notation like "万・億・兆" (man, oku, cho) and exponential notation like "1.2e8."
Since the numbers you handle become quite large in the latter half, I made it possible to change the display method to suit your preference.
For effects, you can choose from normal, subdued, or none. If you're playing for a long time or want to reduce screen shaking, you can change it from settings.
Originally, what I wanted to create was a game based on "the act of stacking itself."
In typical idle games, there's a sense of accomplishment as numbers grow larger. "Sai no Kawara" has that element too, but it also includes mechanisms where stacked things collapse and you let go through samsara.
The subject matter of Sai no Kawara has "stacking" as a straightforward action and "being collapsed despite stacking" as its nature.
From there, it started as a stone-stacking clicking game, and I gradually added mechanisms like Jizo statues, merit, samsara, and long time periods.
As a result, it became a game that's quite simple right after starting, but both the screen and rules change as you progress.
"Sai no Kawara" can be progressed without researching efficiency or strategies from the beginning.
At first, just try stacking stones.
When something is unlocked, check what it does, then stack again. By repeating this, the riverbed that initially had nothing gradually transforms.
I'll gradually compile strategy articles, the samsara mechanism, and hidden elements on Tsukutta.
First, try starting from the empty Sai no Kawara riverbed.
