This is Phase 1. After exploring Plans, you’ll use Schedule Pairs to find combinations.

What is a Plan?#

A Plan is a flexible workspace where you group course instances you’re considering for a specific semester.

Instead of comparing courses in isolation, you create a Plan that says: “I’m thinking about these 4 courses for Spring 2025.” Once they’re in a Plan, you can explore how they interact as a whole.

A Plan doesn’t represent a commitment. It’s a place to think, explore options, and understand trade-offs before deciding anything.

Plans are semester-scoped workspaces. For year-level continuity (completed, ongoing, and planned studies together), see the Year Timeline.

From Courses to Choices#

When planning a semester, the difficulty isn’t picking courses. It’s dealing with their internal choices.

Most courses don’t have a single fixed schedule. They have:

• multiple lecture times,
• multiple exercise groups,
• exams or mandatory sessions.

To reason about how courses interact, Sisukas needs a way to treat these as explicit choices, not hidden details.

Blocks: The Units of Planning#

To make this possible, Sisukas introduces Blocks.

A Block is a user-defined partition over a set of study groups that represents one required selection during schedule computation.

• You must select exactly one study group per block
• Blocks define where choices exist, not what the choices must be
• Blocks are not fixed by SISU — they come from your current partition

By default, Sisukas suggests blocks grouped by activity type (lecture / exercise / exam), but you can repartition study groups however you want.

The Planning Hierarchy#

With that in mind, the planning model looks like this:

• Course Instance
  A specific offering of a course (e.g. CS-A1110, Autumn 2025)

• Block
  A user-defined grouping of study groups representing one required choice
  (defaults group by lecture/exercise/exam)

• Study Group
  A concrete time slot you could attend (e.g. “Tue 14:00–16:00”)

Default partition example (grouped by activity type):

CS-A1110 (Autumn 2025):
├─ Lecture Block
│  └─ Mon/Wed 10:00–12:00
├─ Exercise Block
│  ├─ Group H01 (Tue 14:00–16:00)
│  ├─ Group H02 (Wed 14:00–16:00)
│  └─ Group H03 (Thu 14:00–16:00)
└─ Exam Block
└─ Jan 15, 2026

This structure makes the required selection in a course explicit.

The Composability Principle#

Traditional tools force you to check schedules manually:

• Traditional: “Does this course work?” (in isolation)
• Sisukas: “Do these courses work together?” (in combination)

By treating a Plan as a set of blocks with explicit choices, you can:

• swap one study group for another,
• explore alternatives without rebuilding your whole plan,
• and let the system reason about combinations for you.

This shifts planning from manual trial-and-error to exploring a ranked set of possibilities.

Next Steps#

• Learn how Schedule Pairs combine and rank these choices

See Also#

• The Big Picture – Why we design this way
• Getting Started – Create your first Plan