03 September 2021

BP-1 Stop and Go Traffic: A Synopsis

By James Bishop

Recently players have posted questions online about Moving, Motion, Starting, and Stopping, and how these interact with C6 Target-Based To Hit DRM (Dice Roll Modifiers). These questions appear cyclically, and I can recall answering them for as long as I have played ASL. Much of the information in this article appeared in Ole Bøe’s “Stop and Go Traffic” article, which originally appeared in ASL Annual ‘96. These old Annuals are available as PDF files from MMP, or can be picked up used from all of the usual outlets. I highly recommend you read the original as it's still informative. But for those who can’t, I offer a summary of that article here.1

Moving and Vehicular Target

To apply DRM properly, it's important first to understand the difference between uppercase-Moving and “Moving Vehicular Target.” A Moving Vehicular Target, often referred to simply as a moving target, is defined in C.8. It includes any vehicle during ITS2 Movement Phase (MPh) that has a) entered a new hex, or b) Bypassed a new hexside within its current hex. In addition, any vehicle that a) starts ITS MPh in Motion, or b) is currently in Motion, qualifies as a Moving Vehicular Target. I’ll explain the concept of “Motion” shortly. The key here is that a Moving Vehicular Target is one that has either moved to a new position on the board, or qualifies for Motion status.

Moving is more nuanced. The ASL Rule Book (ASLRB) doesn’t draw a clear distinction between the two primary uses of the term in the game. In its narrowest sense, Moving refers to a unit that is currently conducting ITS MPh. I should stress that only one entity can be said to be Moving (or “phasing”) at a time. However, a Moving entity can consist of more than a single unit. Multiple units can Move as a stack, including Armored Assault (D9.31), which allows an Armored Fighting Vehicle (AFV) and Infantry to Move together. Less common is a “multi-hex stack,” which uses a form of Impulse-based movement.3 In all cases the constituent parts of any Moving group of units are considered Moving regardless of which unit (or units) are actually expending a Movement Factor (MF)/Movement Point (MP) at a given moment. For example, a stack declares Armored Assault. The AFV expends a MP to start, and another to change Vehicular Covered Arc (VCA). Although the Infantry accompanying the AFV has yet to expend any MF, both it and the AFV are Moving, that is, they are conducting THEIR MPh (as a stack). Interestingly, the vehicle does not yet qualify as a Moving Vehicular Target, although it does qualify as a target for Defensive First Fire, which brings me to the broader definition of moving, namely the expenditure of MF/MP.

Rule section A8.1 states that the “portion [of Defensive Fire] occurring during the enemy MPh is called Defensive First Fire and can be used only vs a moving unit(s).” In my previous example, the AFV expended 2 MP. The AFV is therefore moving for the purposes of Defensive First Fire and can be fired upon based on either or both MP expended. The Infantry, however, cannot be targeted directly because they have yet to expend a MF.4 A similar situation occurs when a Stopped vehicle attempts but fails to dispense Smoke at the beginning of ITS MPh. While the vehicle is Moving—in the narrowest sense of the term, it's not moving for the purposes of Defensive First Fire, because it hasn’t expended a MP (D13.2). However, were the vehicle to end ITS MPh at this point, it would qualify for Defensive First Fire, because it's considered to expend all of its remaining MP in that hex (D2.1). This is a case where a vehicle has Moved (conducted ITS MPh) without actually moving anywhere. Confusing, I know. If only such a key concept as “moving” was spelled out in the rules, or defined in the Index.

Stopped and Non-Stopped

The default setting for a vehicle that sets up onboard is Stopped (A2.52). According to the Index, a Non-Stopped vehicle is one that has not expended a Stop MP since its last Start MP expenditure during ITS MPh. A Non-Stopped vehicle is therefore a moving unit in both senses of the term “moving” discussed in the previous paragraph. On the one hand, a Non-Stopped vehicle is conducting ITS MPh. On the other hand, it's moving for the purposes of Defensive First Fire. However, a Non-Stopped vehicle is considered a Moving Vehicular Target only if it has entered a new hex, or used Vehicular Bypass Movement (VBM). So contrary to Stopped status, which can apply during any phase, Non-Stopped status can only apply to a vehicle during ITS MPh. For instance, it’s possible for a vehicle to become Stopped during an enemy Prep Fire Phase as a result of an Immobilization, Shock, or Stun result. But what happens if a vehicle chooses not to end ITS MPh Stopped? 

Motion Status

The term used to describe a vehicle that isn’t Stopped before or after ITS MPh is called Motion. A Moving vehicle—one conducting ITS MPh—is never in Motion. It's either Stopped or Non-Stopped. However, a vehicle which ends ITS MPh without expending a Stop MP assumes Motion status. This status in indicated by placing a Motion counter atop the vehicle. For To-Hit purposes, a Motion vehicle is always treated as a Moving Vehicular Target. Although the Motion counter is removed the moment a vehicle with Motion status begins ITS MPh, the vehicle remains a Moving Vehicular Target. This should be self evident given that the vehicle has yet to expend a Stop MP, and is therefore Non-Stopped, and thus a Moving Vehicular Target. In contrast, a vehicle not under a Motion counter will begin ITS MPh as a Stopped, non-Moving Vehicular Target. 


From the foregoing it should be clear that the game concepts of moving (A8.1), Moving (phasing), and Moving Vehicular Target are not synonymous. A vehicle can be Stopped, yet qualify as a Moving Vehicular Target. Conversely, a vehicle can be Non-Stopped but not qualify as a Moving Vehicular Target. Non-Stopped and Motion, while similar, are not synonymous either. The former represents a state during a unit’s MPh, that is, when a vehicle is Moving. Motion meanwhile is a kind of suspended state of movement that exists outside a unit’s MPh. When in Motion, a vehicle is paradoxically neither moving (A8.1)5 nor Moving (phasing), but is always deemed to be a Moving Vehicular Target, even to the extent of beginning ITS MPh as a Moving Vehicular Target.

A thorough grasp of the implications of each vehicle state and the distinction between moving and Moving, together with a careful perusal of the various charts, will greatly aid you in applying the correct DRM when the rubber meets the road.

Time to see how this all works in practice.

I hope you found this brief article useful. Knowing what DRM apply in a given situation is an important step toward mastery of combined-arms play. Please let me know if you spot any errors. Like you, I’m always learning. Now go read “Stop and Go Traffic!” It’s worth your time. -- jim


1. I (Chris) have taken great liberties editing this piece. Any errors that may have crept in are my own. Hopefully I have not deviated too far from Jim’s intent. You can find Jim's original text here.

2. The Advance Sequence of Play (ASOP) uses all-caps to underscore a) which unit (or group of units) is currently phasing, and b) at what stage a unit (or group of units) is in ITS MPh. A phasing unit conducts ITS MPh in three stages: START, DURING, and END. Although a unit is considered to be Moving, in the sense that it's the unit that is actively phasing, it may not actually be moving for the purposes of A8.1. With the exception of conducting a Search, any actions undertaken by a unit at the START or END of its MPh do not qualify as moving for the purposes of Defensive First Fire, despite the fact that the unit is Moving throughout ITS MPh.

3. In addition to Platoon Movement (D14.2), which allows two or three AFV to Move concurrently in Impulses, there are a number of other special cases where units may Move as a “multi-Location stack” or a “multi-hex stack,” such as Human Wave (A25.23), Cavalry Wave (A13.62), Banzai (G1.5), Convoy (D11.2), and Column (D11.52). Regardless of how many units participate in a Human Wave, for example, the Human Wave Moves as a single entity.

4. The Infantry, while Moving with the AFV, have yet to expend any MF, which means they do not satisfy the broader definition of moving. While the opposing side may declare a Defensive First Fire shot at the AFV, the Infantry may not be targeted (directly) because they are not moving for the purposes of A8.1. A question-and-answer confirms this:

A8.1 & D9.31

Q. An MMC [e.g., a squad] stacked with a stopped AFV declares an Armored Assault. The AFV starts. Does this spent MP allow enemy units to Defensive First Fire at the MMC?

A. No. 

5. Technically there is a fleeting moment at the END of ITS MPh (ASOP Step 3.41A) where a vehicle is moving for purposes of Defensive First Fire. Because a vehicle must either expend a Stop MP or place a Motion counter at the END of ITS MPh, the opposing player is entitled to Defensive First Fire before another unit begins ITS MPh.

1 comment:

Jim Bishop said...

Hey everyone, please let me know if there are comments on this article, particularly if I have made a mistake. I get these reviewed pretty extensively but errors can and will creep in. More importantly, if there is a topic you would like to see me tackle, please let me know. I have three more topics in some semblance of completion. I hope you find these helpful. -- jim